def number_to_name(number):
    """
    Converts an integer called number to a string. 
    Otherwise, it sends an error message letting you know that 
    an invalid choice was made.
    """
    if number == 0:
        return "rock"
    elif number == 1:
        return "Spock"
    elif number == 2:
        return "paper"
    elif number == 3:
        return "lizard"
    elif number == 4:
        return "scissors"
    else:
        return "Not a valid choice"