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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 usn_v4_record(header, record):
 """Extracts USN V4 record information."""

    length, major_version, minor_version = header
    fields = V4_RECORD.unpack_from(record, RECORD_HEADER.size)

    raise NotImplementedError('Not implemented')