Calls receivers callbacks

def call_receivers(self, client, clients_list, message):
        """
        Calls receivers callbacks
        """
        # Try to parse JSON
        try:
            json_message = json.loads(message)
        except ValueError:
            json_message = None

        for func, to_json in self.receivers:

            # Check if json version is available
            if to_json:
                if json_message is None:
                    continue
                msg = json_message
            else:
                msg = message

            # Call callback
            func(client, clients_list, msg)