def complete_proverb(pvb):
    """
    Checks if the proverb is complete.
    Assumes the proverb is converted to have underscores replacing
    unknown letters.
    Assumes everything is uppercase.

    :param pvb: a proverb
    :type pvb: str
    :return: True | False
    :rtype: bool
    """
    if "_" not in pvb:
        return True
    return False