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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 record(self):
        # type: () -> bytes
        '''
        A method to generate the string representing this Directory Record.

        Parameters:
         None.
        Returns:
         String representing this Directory Record.
        '''
        if not self._initialized:
            raise pycdlibexception.PyCdlibInternalError('Directory Record not yet initialized')

        # Ecma-119 9.1.5 says the date should reflect the time when the
        # record was written, so we make a new date now and use that to
        # write out the record.
        self.date = dates.DirectoryRecordDate()
        self.date.new()

        padlen = struct.calcsize(self.FMT) + self.len_fi
        padstr = b'\x00' * (padlen % 2)

        extent_loc = self._extent_location()

        xa_rec = b''
        if self.xa_record is not None:
            xa_rec = b'\x00' * self.xa_pad_size + self.xa_record.record()
        rr_rec = b''
        if self.rock_ridge is not None:
            rr_rec = self.rock_ridge.record_dr_entries()

        outlist = [struct.pack(self.FMT, self.dr_len, self.xattr_len,
                               extent_loc, utils.swab_32bit(extent_loc),
                               self.data_length, utils.swab_32bit(self.data_length),
                               self.date.record(), self.file_flags,
                               self.file_unit_size, self.interleave_gap_size,
                               self.seqnum, utils.swab_16bit(self.seqnum),
                               self.len_fi) + self.file_ident + padstr + xa_rec + rr_rec]

        outlist.append(b'\x00' * (len(outlist[0]) % 2))

        return b''.join(outlist)