+ $activityContacts = CRM_Core_PseudoConstant::activityContacts('name');
+ $sourceID = CRM_Utils_Array::key('Activity Source', $activityContacts);
+ $assigneeID = CRM_Utils_Array::key('Activity Assignees', $activityContacts);
+ $targetID = CRM_Utils_Array::key('Activity Targets', $activityContacts);
+