bots: Modify is_private function to take id as the input.

This is done so that Embedded bot system can also make use of
this function directly, as only id is needed in this function.

Also, there would be ambiguity as what type of BotHandler is
passed in the arguments: EmbeddedBotHandler or ExternalBotHandler.

Author: abhijeetkaur

zulip_bots/zulip_bots/lib.py

@@ -175,12 +175,18 @@ def extract_query_without_mention(message, client):
     query_without_mention = message['content'][len(start_with_mention.group()):]
     return query_without_mention.lstrip()
 
-def is_private(message, client):
-    # type: (Dict[str, Any], ExternalBotHandler) -> bool
-    # bot will not reply if the sender id is the same as the bot id
-    # to prevent infinite loop
+def is_private(message, at_mention_bot_id):
+    # type: (Dict[str, Any], int) -> bool
+    """
+    This function is to ensure that the bot doesn't go into infinite loop if the message sender id is
+    the same as the id of the bot which is called. This function makes the bot not reply to itself.
+
+    This function is being leveraged by two systems; external bot system and embedded bot system,
+    any change/modification in the structure of this should be reflected at other places accordingly.
+    For details read "extract_query_without_mention" function docstring.
+    """
     if message['type'] == 'private':
-        return client.id != message['sender_id']
+        return at_mention_bot_id != message['sender_id']
     return False
 
 def run_message_handler_for_bot(lib_module, quiet, config_file, bot_name):
@@ -212,7 +218,7 @@ def handle_message(message):
         # is_mentioned is true if the bot is mentioned at ANY position (not necessarily
         # the first @mention in the message).
         is_mentioned = message['is_mentioned']
-        is_private_message = is_private(message, restricted_client)
+        is_private_message = is_private(message, restricted_client.id)
 
         # Strip at-mention botname from the message
         if is_mentioned: