+=item edit_advertising_source OPTION => VALUE, ...
+
+Edit a advertising source.
+
+=over
+
+=item secret
+
+API Secret
+
+=item refnum
+
+Referral number to edit
+
+=item source
+
+hash of edited source fields.
+
+=over
+
+=item referral
+
+Referral name
+
+=item disabled
+
+Referral disabled, Y for disabled or nothing for enabled
+
+=item agentnum
+
+Agent ID number
+
+=item title
+
+External referral ID
+
+=back
+
+=back
+
+Example:
+
+ my $result = FS::API->edit_advertising_source(
+ 'secret' => 'sharingiscaring',
+ 'refnum' => '4', # referral number to edit
+ 'source' => {
+ #optional
+ 'referral' => 'test referral',
+ 'disabled' => 'Y',
+ 'agentnum' => '2', #agent id number
+ 'title' => 'test title',
+ }
+ );
+
+ if ( $result->{'error'} ) {
+ die $result->{'error'};
+ } else {
+ # edit_advertising_source returns updated source upon success.
+ print Dumper($result);
+ }
+
+=cut
+
+#edit_advertising_source