def simple_check(author, channel):
    """
    A predicate used in the wait_for() function, to ensure the user input can only come
    from the user who activated the command, and in the same channel.
    :param author: Author object
    :param channel: Channel object
    :return: Check function
    """

    def check(message):
        return message.author == author and message.channel == channel

    return check