def errors(number):
    """ Raises NegativeNumberError if number less than 0, and
    raises ZeroNumberException if number is equal to 0."""
    
    if number < 0:
        raise NegativeNumberError,\
            "\n<The number must be greater or equal to 0 \n"
    elif number == 0:
        raise ZeroNumberException,\
            "\n<It is agreed per convention that 0!= 1 \n"
    elif number >0:
        pass 
    
    return number
 Raises NegativeNumberError if number less than 0, and
    raises ZeroNumberException if number is equal to 0.
recipes/Python/576616_FactorialLambda/recipe-576616.py