




'''simple docstring'''





def      UpperCamelCase_(	snake_case							:       str     ):

							'''simple docstring'''






							return credit_card_number.startswith(("34", "35", "37", "4", "5", "6")     )


def      UpperCamelCase_(	snake_case							:       str     ):

							'''simple docstring'''






							snake_case_						=      credit_card_number
							snake_case_						=      0
							snake_case_						=      len(snake_case     ) - 2
							for i in range(snake_case							,				-1							,				-2     ):
														#  double the value of every second digit
														snake_case_						=      int(cc_number[i]     )
														digit *= 2
														# If doubling of a number results in a two digit number
														# i.e greater than 9(e.g., 6 × 2 = 12),
														# then add the digits of the product (e.g., 12: 1 + 2 = 3, 15: 1 + 5 = 6),
														# to get a single digit number.
														if digit > 9:
																					digit %= 1_0
																					digit += 1
														snake_case_						=      cc_number[:i] + str(snake_case     ) + cc_number[i + 1 :]
														total += digit

							# Sum up the remaining digits
							for i in range(len(snake_case     ) - 1							,				-1							,				-2     ):
														total += int(cc_number[i]     )

							return total % 1_0 == 0


def      UpperCamelCase_(	snake_case							:       str     ):

							'''simple docstring'''






							snake_case_						=      f'{credit_card_number} is an invalid credit card number because'
							if not credit_card_number.isdigit():
														print(f'{error_message} it has nonnumerical characters.'     )
														return False

							if not 1_3 <= len(snake_case     ) <= 1_6:
														print(f'{error_message} of its length.'     )
														return False

							if not validate_initial_digits(snake_case     ):
														print(f'{error_message} of its first two digits.'     )
														return False

							if not luhn_validation(snake_case     ):
														print(f'{error_message} it fails the Luhn check.'     )
														return False

							print(f'{credit_card_number} is a valid credit card number.'     )
							return True


if __name__ == "__main__":
		import doctest

		doctest.testmod()
		validate_credit_card_number("4111111111111111")
		validate_credit_card_number("32323")












def 						_a    (      a :int )							->			bool:
 a		  =      n ** (1 / 3)
 return (val * val * val) == n


if __name__ == "__main__":
     print(perfect_cube(27))
     print(perfect_cube(4))


