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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 decode_base64(data: str) -> bytes: """Decode base64, padding being optional. :param data: Base64 data as an ASCII byte string :returns: The decoded byte string. """

    missing_padding = len(data) % 4
    if missing_padding != 0:
        data += "=" * (4 - missing_padding)
    return base64.decodebytes(data.encode("utf-8"))