<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _already_in(self, option):
 """ Check if an option is already in the message. :type option: Option :param option: the option to be checked :return: True if already present, False otherwise """

        for opt in self._options:
            if option.number == opt.number:
                return True
        return False