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<!-- Module User's Guide -->

<chapter xmlns:xi="http://www.w3.org/2001/XInclude">
	<title>&adminguide;</title>

    
    <section>
    <title>Overview</title>
    <para> The Kazoo is a general purpose AMQP connector (tested with rabbitmq-server). It exposes publish/consume capabilities into Kamailio.
    </para>
<para>
From a high-level, the purpose of the module might be for things like:
<itemizedlist>
<listitem>
<para>
Integrate to an AMQP application to make real-time routing decisions (instead of using, say, a SQL database)
</para>
</listitem>
<listitem>
<para>
Provide a real-time integration into your program, instead of your database, so you can overlay additional logic in your preferred language while also utilizing a message bus
</para>
</listitem>
<listitem>
<para>
Utilize messaging to have a distributed messaging layer, such that machines processing requests/responses/events can go up/down or share the workload and your Kamailio node will still be happy
</para>
</listitem>
</itemizedlist>
</para>


<para>
supported operations are:
<itemizedlist>
<listitem>
<para>
publish json payloads to rabbitmq
</para>
</listitem>
<listitem>
<para>
publish json payloads to rabbitmq and wait for correlated response message
</para>
</listitem>
<listitem>
<para>
subscribe to an exchange with a routing key
</para>
</listitem>
</itemizedlist>
</para>
<para>
The Kazoo module also has support to publish updates to presence module thru the kazoo_pua_publish function
</para>

</section>
    <section>
    <title>How it works</title>
<para>  
The module works with a main forked process that does the communication with rabbitmq for issuing publishes, waiting for replies and consuming messages. When it consumes a message it defers the process to a worker process so that it doesn't block this main process.
</para>
    <section>
    <title>event routes</title>
    <para>
The worker process issues an event-route where we can act on the received payload. The name of the event-route is composed by values extracted from the payload.
    </para>
    <para>
    Kazoo module will try to execute the event route from most significant to less significant. 
    define the event route like event_route[kazoo:consumer-event[-payload_key_value[-payload_subkey_value]]]
    </para>
    <para>
    we can set the key/subkey pair on a subscription base. check the payload on subscribe.
    </para>
        <example>
        <title>define the event route</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_event_key", "Event-Category")
modparam("kazoo", "amqp_consumer_event_subkey", "Event-Name")
...

event_route[kazoo:consumer-event-presence-update]
{
# presence is the value extracted from Event-Category field in json payload 
# update is the value extracted from Event-Name field in json payload 
xlog("L_INFO", "received $(kzE{kz.json,Event-Package}) update for $(kzE{kz.json,From})");
...
}

event_route[kazoo:consumer-event-presence]
{
# presence is the value extracted from Event-Category field in json payload 
xlog("L_INFO", "received $(kzE{kz.json,Event-Package}) update for $(kzE{kz.json,From})");
...
}

event_route[kazoo:consumer-event-event-category-event-name]
{
# event-category is the name of the amqp_consumer_event_key parameter
# event-name is the name of the amqp_consumer_event_subkey parameter
# this event route is executed if we can't find the previous 
...
}

event_route[kazoo:consumer-event-event-category]
{
# event-category is the name of the amqp_consumer_event_key parameter
# this event route is executed if we can't find the previous 
...
}

event_route[kazoo:consumer-event]
{
# this event route is executed if we can't find the previous 
}

</programlisting>
        </example>
</section>
    <section>
    <title>acknowledge messages</title>
<para>
Consumed messages have the option of being acknowledge in two ways:
<itemizedlist>
<listitem>
<para>
immediately when received 
</para>
</listitem>
<listitem>
<para>
after processing by the worker 
</para>
</listitem>
</itemizedlist>

    </para>
    
</section>
    </section>

    <section>
    <title>Dependencies</title>
    <section>
        <title>&kamailio; Modules</title>
        <para>
        The following modules must be loaded before this module:
            <itemizedlist>
            <listitem>
            <para>
                <emphasis>none</emphasis>.
            </para>
            </listitem>
            </itemizedlist>
        </para>
    </section>
    <section>
        <title>External Libraries or Applications</title>
        <itemizedlist>
            <listitem>
            <para>
                <emphasis>librabbitmq</emphasis>.
            </para>
            </listitem>
            <listitem>
            <para>
                <emphasis>libjson</emphasis>.
            </para>
            </listitem>
            <listitem>
            <para>
                <emphasis>libuuid</emphasis>.
            </para>
            </listitem>
        </itemizedlist>

        </section>
    </section>
    
    
    <section>
    <title>Parameters</title>
    <section>
    <title>amqp related</title>
    <section>
        <title><varname>node_hostname</varname>(str)</title>
        <para>
        The name of this host to register in rabbitmq.
        </para>
        <para>
        <emphasis>Default value is NULL. you must set this parameter value for the module to work</emphasis>
        </para>
        <example>
        <title>Set <varname>node_hostname</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "node_hostname", "sipproxy.mydomain.com")
...
</programlisting>
        </example>
    </section>
    <section>
        <title><varname>amqp_consumer_processes</varname>(int)</title>
        <para>
        The number of worker processes to handle messages consumption.
        </para>
        <para>
        <emphasis>Default value is 4.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_processes</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_processes", 10)
...
</programlisting>
        </example>
    </section>

    <section>
        <title><varname>amqp_consumer_event_key</varname>(str)</title>
        <para>
        The default name of the field in json payload to compose the event name 1st part
        </para>
        <para>
        <emphasis>Default value is <quote>Event-Category</quote>.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_event_key</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_event_key", "My-JSON-Field-Name")
...
</programlisting>
        </example>
    </section>

    <section>
        <title><varname>amqp_consumer_event_subkey</varname>(str)</title>
        <para>
        The default name of the field in json payload to compose the event name 2nd part
        </para>
        <para>
        <emphasis>Default value is <quote>Event-Name</quote>.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_event_subkey</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_event_subkey", "My-JSON-SubField-Name")
...
</programlisting>
        </example>
    </section>

    <section>
        <title><varname>amqp_max_channels</varname>(str)</title>
        <para>
        The number of pre allocated channels for the connection.
        </para>
        <para>
        <emphasis>Default value is 50.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_max_channels</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_max_channels", 100)
...
</programlisting>
        </example>
    </section>

    <section>
        <title><varname>amqp_connection</varname>(str)</title>
        <para>
        The connection url to rabbitmq. can be set multiple times for failover.
        </para>
        <example>
        <title>Set <varname>amqp_connection</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_connection", "amqp://guest:guest@localhost:5672")
modparam("kazoo", "amqp_connection", "kazoo://guest:guest@otherhost:5672")
...
</programlisting>
        </example>
    </section>

<section>
  <title><varname>event_callback</varname>(str)</title>
    <para>
        The name of the function in the kemi configuration file (embedded
        scripting language such as Lua, Python, ...) to be executed instead
        of event_route[...] blocks.
    </para>
    <para>
        The function receives a string parameter with the name of the event,
        the values can be: 'kazoo:mod-init', 'kazoo:consumer-event'.
    </para>

  <example>
    <title>Set <varname>event_callback</varname> parameter</title>
    <programlisting format="linespecific">
    ...
    modparam("kazoo", "event_callback", "ksr_kazoo_event")
    ...
    </programlisting>
  </example>
</section>

    

    


    </section>

    <section>
    <title>execution control</title>
    <para>execution control of main loop can be controlled by changing the parameter values in this section.</para>
    <para>The main loop has 3 sub-loops were it listen for actions to execute with a timeout. These group of parameters allow to set the maximum number of times the sub-loop is executed if it doesn't timeout.</para>
    <para>On busy systems, we may have a condition where a sub-loop never times out because it always has data to process. The purpose of these parameters is to set a maximum number of times it executes before it handles control to the next sub-loop.</para>
        <programlisting format="linespecific">
...
while(true) // main  loop
 while(ACK or timeout)  // acknowledge from worker process
 while(SEND or timeout) // anything to send ?
 while(CONSUME or timeout) // any data on consumed exchanges ?
...
</programlisting>

    <section>
        <title><varname>amqp_consumer_loop_count</varname>(int)</title>
        <para>
        The consumer loop count.
        </para>
        <para>
        <emphasis>Default value is 10.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_loop_count</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_loop_count", 3)
...
</programlisting>
        </example>
    </section>    
    
    <section>
        <title><varname>amqp_internal_loop_count</varname>(int)</title>
        <para>
        The internal listen for commands loop count.
        </para>
        <para>
        <emphasis>Default value is 5.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_internal_loop_count</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_internal_loop_count", 1)
...
</programlisting>
        </example>
    </section>    
    
    <section>
        <title><varname>amqp_consumer_ack_loop_count</varname>(int)</title>
        <para>
        The work ack loop count.
        </para>
        <para>
        <emphasis>Default value is 20.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_ack_loop_count</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_ack_loop_count", 5)
...
</programlisting>
        </example>
    </section><section>
        <title><varname>consume_messages_on_reconnect</varname>(int)</title>
        <para>
        This parameter indicates if the module ignores the loop counters on reconnect and consumes all the pending messages ready to be consumed.
        </para>
        <para>
        <emphasis>Default value is 1.</emphasis>
        </para>
        <example>
        <title>Set <varname>consume_messages_on_reconnect</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "consume_messages_on_reconnect", 0)
...
</programlisting>
        </example>
    </section><section>
        <title><varname>single_consumer_on_reconnect</varname>(int)</title>
        <para>
        When the main loop receives a message from rabbitmq it will defer the execution to a worker in a round-robin manner. this parameter allows to use the same worker when kazoo reconnects to rabbitmq.
        </para>
        <para>
        <emphasis>Default value is 1.</emphasis>
        </para>
        <example>
        <title>Set <varname>single_consumer_on_reconnect</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "single_consumer_on_reconnect", 0)
...
</programlisting>
        </example>
    </section>    
    
    
    </section>

    <section>
    <title>timers</title>
    <para>
    each functional parameter related to timers come with 2 reflected parameters. name_sec and name_micro 
    </para>
    <section>
        <title><varname>amqp_consumer_ack_timeout</varname>(str)</title>
        <para>
        Timeout when checking for acknowledge from workers.
        </para>
        <para>
        <emphasis>Default value is 100000 micro.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_consumer_ack_timeout</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_consumer_ack_timeout_sec", 1)
modparam("kazoo", "amqp_consumer_ack_timeout_micro", 200000)
...
</programlisting>
        </example>
    </section>    

    <section>
        <title><varname>amqp_interprocess_timeout</varname>(str)</title>
        <para>
        Timeout when checking for commands (publish/query) for sending to rabbitmq.
        </para>
        <para>
        <emphasis>Default value is 100000 micro.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_interprocess_timeout</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_interprocess_timeout_sec", 1)
modparam("kazoo", "amqp_interprocess_timeout_micro", 200000)
...
</programlisting>
        </example>
    </section>    

    <section>
        <title><varname>amqp_waitframe_timeout</varname>(str)</title>
        <para>
        Timeout when checking for messages from rabbitmq.
        </para>
        <para>
        <emphasis>Default value is 100000 micro.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_waitframe_timeout</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_waitframe_timeout_sec", 1)
modparam("kazoo", "amqp_waitframe_timeout_micro", 200000)
...
</programlisting>
        </example>
    </section>    

    <section>
        <title><varname>amqp_query_timeout</varname>(str)</title>
        <para>
        Timeout when checking for reply messages from rabbitmq for kazoo_query commands.
        </para>
        <para>
        <emphasis>Default value is 2 sec.</emphasis>
        </para>
        <example>
        <title>Set <varname>amqp_query_timeout</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_query_timeout_sec", 1)
modparam("kazoo", "amqp_query_timeout_micro", 200000)
...
</programlisting>
        </example>
    </section>    
 
     <section>
        <title><varname>amqp_query_timeout_avp</varname>(str)</title>
        <para>
        avp holding the value in seconds for Timeout when checking for reply messages from rabbitmq for kazoo_query commands.
        </para>
        <para>
        <emphasis>Default value is NULL (no value).</emphasis>
        </para>
        <example>
        <title>>Set <varname>amqp_query_timeout_avp</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "amqp_query_timeout_avp", "$var(kz_timeout)")

route[SOME_ROUTE]
{
    $var(kz_timeout) = 12;
    kazoo_query(exchange, routingkey, payload);
}    

...
</programlisting>
        </example>
    </section>    
 
 
    </section>
        
    <section>
    <title>presence related</title>
    <section>
        <title><varname>db_url</varname>(str)</title>
        <para>
        The database for the presentity table.
        </para>
        <para>If set, the kazoo_ppua_publish function will update the presentity status in the database.
        </para>
        <para>
        <emphasis>Default value is <quote>NULL</quote>.</emphasis>
        </para>
        <example>
        <title>Set <varname>db_url</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "db_url", "&defaultdb;")
...
</programlisting>
        </example>
    </section>

    <section>
        <title><varname>presentity_table</varname>(str)</title>
        <para>
        The name of the presentity table in the database.
        </para>
        <para>
        <emphasis>Default value is <quote>presentity</quote>.</emphasis>
        </para>
        <example>
        <title>Set <varname>presentity_table</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "presentity_table", "my_presentity_table")
...
</programlisting>
        </example>
    </section>

    <section id="kazoo.p.pua_mode">
        <title><varname>pua_mode</varname>(int)</title>
		<para>
			Control if the module has to connect to presence database tables.
			Set it to 0 to not connect to database.
		</para>
        <para>
        <emphasis>Default value is <quote>1</quote>.</emphasis>
        </para>
        <example>
        <title>Set <varname>pua_mode</varname> parameter</title>
        <programlisting format="linespecific">
...
modparam("kazoo", "pua_mode", 0)
...
</programlisting>
        </example>
    </section>

    </section>
    
    
    


</section>    
<section>
    <title>Functions</title>
    <section>
    <title>amqp related</title>

    <section>
        <title>
        <function moreinfo="none">kazoo_publish(exchange, routing_key, json_payload)</function>
        </title>
        <para>
        The function publishes a json payload to rabbitmq. The routing_key parameter should be encoded.
        </para>
        <para>
        This function can be used from ANY ROUTE.
        </para>

        <example>
        <title><function>kazoo_publish</function> usage</title>
        <programlisting format="linespecific">
...
$var(amqp_payload_request) = $_s({"Event-Category" : "directory", "Event-Name" : "reg_success", "Contact" : "$(ct{s.escape.common}{s.replace,\','}{s.replace,$$,})", "Call-ID" : "$ci", "Realm" : "$fd", "Username" : "$fU", "From-User" : "$fU", "From-Host" : "$fd", "To-User" : "$tU", "To-Host" : "$td", "User-Agent" : "$(ua{s.escape.common}{s.replace,\','}{s.replace,$$,})" });
$var(amqp_routing_key) = "registration.success." + $(fd{kz.encode}) + "." + $fU;
kazoo_publish("callmgr", $var(amqp_routing_key), $var(amqp_payload_request)); 
...
</programlisting>
        </example>
    </section>
    
    <section>
        <title>
        <function moreinfo="none">kazoo_query(exchange, routing_key, json_payload [, target_var])</function>
        </title>
        <para>
        The function publishes a json payload to rabbitmq, waits for a correlated messageand puts the result in target_var. The routing_key parameter should be encoded.
        target_var is optional as the function also puts the result in pseudo-variable $kzR.
        </para>
        <para>
        This function can be used from ANY ROUTE.
        </para>

        <example>
        <title><function>kazoo_query</function> usage</title>
        <programlisting format="linespecific">
...
$var(amqp_payload_request) = "{'Event-Category' : 'call_event' , 'Event-Name' : 'query_user_channels_req', 'Realm' : '" + $fd + "', 'Username' : '" + $fU + "', 'Active-Only' : false }";
kazoo_encode("$ci", "$var(callid_encoded)");
$var(amqp_routing_key) = "call.status_req.$var(callid_encoded)";
if(kazoo_query("callevt", $var(amqp_routing_key), $var(amqp_payload_request), "$var(amqp_result)")) {
   kazoo_json("$var(amqp_result)", "Channels[0].switch_url", "$du");
   if($du != $null) {
       xlog("L_INFO", "$ci|log|user channels found redirecting call to $du");
       return;
   }
}
...
</programlisting>
        </example>
    </section>
    
    <section>
        <title>
        <function moreinfo="none">kazoo_subscribe(exchange, exchange_type, queue, routing_key)</function>
        </title>
        <para>
        The function subscribes to exchange/type on queue with routing_key. The routing_key parameter should be encoded.
        </para>
        <para>
        This function  must be called from event_route[kazoo:mod-init].
        </para>

        <example>
        <title><function>kazoo_subscribe</function> usage</title>
        <programlisting format="linespecific">
...
event_route[kazoo:mod-init]
{
   kazoo_subscribe("dialoginfo", "direct", "BLF-QUEUE-MY_HOSTNAME", "BLF-MY_HOSTNAME");
}

event_route[kazoo:consumer-event]
{
    xlog("L_INFO","Received json payload : $kzE");
}
...
</programlisting>
        </example>
    </section>

    <section>
        <title>
        <function moreinfo="none">kazoo_subscribe(json_description)</function>
        </title>
        <para>
        The function takes additional parameters to the subscribe function.
        </para>
        <para>        
        <itemizedlist>
            <title>json payload fields description</title>
            <listitem>
               <para>exchange : str, required</para> 
            </listitem>
            <listitem>
               <para>type : str, required</para> 
            </listitem>
            <listitem>
               <para>queue : str, required</para> 
            </listitem>
            <listitem>
               <para>routing : str, required</para> 
            </listitem>
            <listitem>
               <para>auto_delete : int, default 1</para> 
            </listitem>
            <listitem>
               <para>durable : int, default 0</para> 
            </listitem>
            <listitem>
               <para>no_ack : int, default 1</para> 
            </listitem>
            <listitem>
               <para>wait_for_consumer_ack : int, default 0</para> 
            </listitem>
            <listitem>
               <para>event_key : str, no default</para> 
            </listitem>
            <listitem>
               <para>event_subkey : str, no default</para> 
            </listitem>
        </itemizedlist>
        </para>
        <para>
        This function  must be called from event_route[kazoo:mod-init].
        </para>
        <example>
        <title><function>kazoo_subscribe</function> usage</title>
        <programlisting format="linespecific">
...
event_route[kazoo:mod-init]
{
    $var(payload) = "{ 'exchange' : 'dialoginfo' , 'type' : 'direct', 'queue' : 'BLF-QUEUE-MY_HOSTNAME', 'routing' : 'BLF-MY_HOSTNAME', 'auto_delete' : 0, 'durable' : 1, 'no_ack' : 0, 'wait_for_consumer_ack' : 1 }";
    kazoo_subscribe("$var(payload)");
}

event_route[kazoo:consumer-event]
{
    xlog("L_INFO","Received json payload : $kzE");
}
...
</programlisting>
        </example>
    </section>
    
</section>
    <section>
    <title>presence related</title>
    <section>
        <title>
        <function moreinfo="none">kazoo_pua_publish(json_payload)</function>
        </title>
        <para>
        The function build presentity state from json_payload and updates presentity table.
        </para>
        <para>
        This function can be used from ANY ROUTE.
        </para>

        <example>
        <title><function>kazoo_pua_publish</function> usage</title>
        <programlisting format="linespecific">
...
event_route[kazoo:consumer-event-presence-update]
{
    xlog("L_INFO", "received $(kzE{kz.json,Event-Package}) update for $(kzE{kz.json,From})");
    kazoo_pua_publish($kzE);
    pres_refresh_watchers("$(kzE{kz.json,From})", "$(kzE{kz.json,Event-Package})", 1);
}    
...
</programlisting>
        </example>
    </section>

    
</section>
    <section>
    <title>other</title>
    <section>
        <title>
        <function moreinfo="none">kazoo_encode(to_encode, target_var)</function>
        </title>
        <para>
        The function encodes the 1st parameter for amqp and puts the result in the 2nd parameter.
        </para>
        <para>
        This function can be used from ANY ROUTE.
        </para>

        <example>
        <title><function>kazoo_encode</function> usage</title>
        <programlisting format="linespecific">
...
kazoo_encode("$ci", "$var(callid_encoded)");
$var(amqp_routing_key) = "call.status_req.$var(callid_encoded)";
...
</programlisting>
        </example>
    </section>

    <section>
        <title>
        <function moreinfo="none">kazoo_json(json_payload, field, target_var)</function>
        </title>
        <para>
        The function extracts the value from a json payload and puts the result in the 3rd parameter.
        It can use nested values for the query part.
        </para>
        <para>
        This function can be used from ANY ROUTE.
        </para>

        <example>
        <title><function>kazoo_json</function> usage</title>
        <programlisting format="linespecific">
...
kazoo_json("$var(amqp_result)", "Channels[0].switch_url", "$du");
if($du != $null) {
  xlog("L_INFO", "$ci|log|user channels found redirecting call to $du");
  return;
}
...
</programlisting>
        </example>
    </section>
    
</section>
</section>
    
        <section>
        <title>Exported pseudo-variables</title>
        <itemizedlist>
            <listitem>
            <para>
                <emphasis>$kzR</emphasis>
                Contains the payload result of kazoo_query execution.
            </para>
            </listitem>
            <listitem>
            <para>
                <emphasis>$kzE</emphasis>
                Contains the payload of a consumed message
            </para>
            </listitem>
        </itemizedlist>
    </section>
    
        <section>
        <title>Transformations</title>
        <para>The prefix for kazoo transformations is kz.</para>
        <itemizedlist>
            <listitem><para>
                <emphasis>json</emphasis>
            </para>
        <example>
        <title><function>kz.json</function> usage</title>
        <programlisting format="linespecific">
...
#kazoo_json("$var(amqp_result)", "Channels[0].switch_url", "$du");
$du = $kzR{kz.json,Channels[0].switch_url};
if($du != $null) {
  xlog("L_INFO", "$ci|log|user channels found redirecting call to $du");
  return;
}
...
</programlisting>
        </example>
            
            </listitem>
            <listitem><para>
                <emphasis>encode</emphasis>
            </para>
        <example>
        <title><function>kz.encode</function> usage</title>
        <programlisting format="linespecific">
...
#kazoo_encode("$ci", "$var(callid_encoded)");
#$var(amqp_routing_key) = "call.status_req.$var(callid_encoded)";
$var(amqp_routing_key) = "call.status_req." + $(ci{kz.encode})
...
</programlisting>
        </example>
            
            </listitem>
        </itemizedlist>
    </section>
    

</chapter>