Find out if you are in a channel.
        Required arguments:
        * channel - Channel to check whether you are in it or not.
        * should_be - If True, raise an exception if you aren't in the channel;
                    If False, raise an exception if you are in the channel.

def is_in_channel(self, channel, should_be=True):
        """
        Find out if you are in a channel.
        Required arguments:
        * channel - Channel to check whether you are in it or not.
        * should_be - If True, raise an exception if you aren't in the channel;
                    If False, raise an exception if you are in the channel.
        """
        with self.lock:
            for channel_ in self.channels:
                if self.compare(channel_, channel):
                    if not should_be:
                        raise \
                    self.AlreadyInChannel('LurklibError: AlreadyInChannel')
                    return None
            if should_be:
                raise self.NotInChannel('LurklibError: NotInChannel')