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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 _non_framed_body_length(header, plaintext_length):
 """Calculates the length of a non-framed message body, given a complete header. :param header: Complete message header object :type header: aws_encryption_sdk.structures.MessageHeader :param int plaintext_length: Length of plaintext in bytes :rtype: int """

    body_length = header.algorithm.iv_len  # IV
    body_length += 8  # Encrypted Content Length
    body_length += plaintext_length  # Encrypted Content
    body_length += header.algorithm.auth_len  # Authentication Tag
    return body_length