#145EasyFunctions· Decomposition

ISBN-10 Validator

An ISBN-10 is a 10-character book number whose last character is a check digit that catches typing mistakes. Write `is_valid_isbn10(code)` that returns `True` when `code` is a valid ISBN-10: - Hyphens and spaces may appear anywhere and are ignored. - What remains must be exactly 10 characters: nine digits followed by a digit or `X` (either case), where `X` stands for 10. - Multiply the first character's value by 10, the second by 9, and so on down to the last by 1. The code is valid when the sum of these products is divisible by 11.

Input format

`code`: a string.

Output format

`true` or `false`.

Examples

Input: code = "0-306-40615-2"

Output: true

0*10 + 3*9 + 0*8 + 6*7 + 4*6 + 0*5 + 6*4 + 1*3 + 5*2 + 2*1 = 132 = 12 * 11.

Input: code = "0-306-40615-3"

Output: false

Changing the check digit breaks the checksum.

Constraints

0 <= len(code) <= 50

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