def in_proverb(guess, pvb):
    """
    Checks if the player's guess is in the proverb.
    Assumes everything is uppercase.

    :param guess: a single letter
    :type guess: str
    :param pvb: the proverb
    :type pvb: str
    :return: True | False
    :rtype: bool
    """
    if guess in pvb:
        return True
    return False