code: def capture_message(self, message, level=None):
          # type: (str, Optional[Any]) -> Optional[str]
          
          if self.client is None:
              return None
          if level is None:
              level = "info"
          return self.capture_event({"message": message, "level": level})
docs: Captures a message.  The message is just a string.  If no level
          is provided the default level is `info`.