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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 _run_dpkt(self, dpkt):
 """Call dpkt.pcap.Reader to extract PCAP files."""

        # if not self._flag_a:
        #     self._flag_a = True
        #     warnings.warn(f"'Extractor(engine=dpkt)' object is not iterable; "
        #                     "so 'auto=False' will be ignored", AttributeWarning, stacklevel=stacklevel())

        if self._exlyr != 'None' or self._exptl != 'null':
            warnings.warn("'Extractor(engine=dpkt)' does not support protocol and layer threshold; "
                          f"'layer={self._exlyr}' and 'protocol={self._exptl}' ignored",
                          AttributeWarning, stacklevel=stacklevel())

        # extract global header
        self.record_header()
        self._ifile.seek(0, os.SEEK_SET)

        # extract & analyse file
        self._expkg = dpkt
        self._extmp = iter(dpkt.pcap.Reader(self._ifile))

        # start iteration
        self.record_frames()