<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_check(self, func, *, call_once=False):
 """Adds a global check to the bot. This is the non-decorator interface to :meth:`.check` and :meth:`.check_once`. Parameters func The function that was used as a global check. call_once: :class:`bool` If the function should only be called once per :meth:`.Command.invoke` call. """


        if call_once:
            self._check_once.append(func)
        else:
            self._checks.append(func)