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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 verify_checksum(message, previous_csum=0):
 """Verify checksum for incoming message. :param message: incoming message :param previous_csum: accumulated checksum value :return return True if message checksum type is None or checksum is correct """

    if message.message_type in CHECKSUM_MSG_TYPES:
        csum = compute_checksum(
            message.checksum[0],
            message.args,
            previous_csum,
        )

        if csum == message.checksum[1]:
            return True
        else:
            return False
    else:
        return True