def serialize(self,writer: SerializationWriter) -> None:
        """
        Serializes information the current object
        param writer: Serialization writer to use to serialize this model
        Returns: None
        """
        if writer is None:
            raise TypeError("writer cannot be null.")
        writer.write_str_value("clientContext", self.client_context)
        writer.write_object_value("customPrompt", self.custom_prompt)
        writer.write_additional_data_value(self.additional_data)

        Serializes information the current object
        param writer: Serialization writer to use to serialize this model
        Returns: None
        
msgraph/generated/communications/calls/item/participants/item/start_hold_music/start_hold_music_post_request_body.py