code: def add_check(self, func, *, call_once=False):
          
  
          if call_once:
              self._check_once.append(func)
          else:
              self._checks.append(func)
docs: 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.