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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def base64url_decode(msg):
 """ Decode a base64 message based on JWT spec, Appendix B. "Notes on implementing base64url encoding without padding" """

    rem = len(msg) % 4
    if rem:
        msg += b'=' * (4 - rem)

    return base64.urlsafe_b64decode(msg)