How to use the minidump.StreamDirectory function in minidump

def parse_content(self):
        """Build structures corresponding to current content"""

        # Header
        offset = 0
        self.minidumpHDR = mp.MinidumpHDR.unpack(self._content, offset, self)
        assert self.minidumpHDR.Magic == 0x504d444d

        # Streams
        base_offset = self.minidumpHDR.StreamDirectoryRva.rva
        empty_stream = mp.StreamDirectory(StreamType=0,
                                          Location=mp.LocationDescriptor(DataSize=0,
                                                                         Rva=mp.Rva(rva=0)
                                          )
        )
        streamdir_size = len(empty_stream)
        for i in xrange(self.minidumpHDR.NumberOfStreams):
            stream_offset = base_offset + i * streamdir_size
            stream = mp.StreamDirectory.unpack(self._content, stream_offset, self)
            self.streams.append(stream)

            # Launch specific action depending on the stream
            datasize = stream.Location.DataSize
            offset = stream.Location.Rva.rva
            if stream.StreamType == mp.streamType.ModuleListStream:
                self.modulelist = mp.ModuleList.unpack(self._content, offset, self)
            elif stream.StreamType == mp.streamType.MemoryListStream:

# Header
        offset = 0
        self.minidumpHDR = mp.MinidumpHDR.unpack(self._content, offset, self)
        assert self.minidumpHDR.Magic == 0x504d444d

        # Streams
        base_offset = self.minidumpHDR.StreamDirectoryRva.rva
        empty_stream = mp.StreamDirectory(StreamType=0,
                                          Location=mp.LocationDescriptor(DataSize=0,
                                                                         Rva=mp.Rva(rva=0)
                                          )
        )
        streamdir_size = len(empty_stream)
        for i in xrange(self.minidumpHDR.NumberOfStreams):
            stream_offset = base_offset + i * streamdir_size
            stream = mp.StreamDirectory.unpack(self._content, stream_offset, self)
            self.streams.append(stream)

            # Launch specific action depending on the stream
            datasize = stream.Location.DataSize
            offset = stream.Location.Rva.rva
            if stream.StreamType == mp.streamType.ModuleListStream:
                self.modulelist = mp.ModuleList.unpack(self._content, offset, self)
            elif stream.StreamType == mp.streamType.MemoryListStream:
                self.memorylist = mp.MemoryList.unpack(self._content, offset, self)
            elif stream.StreamType == mp.streamType.Memory64ListStream:
                self.memory64list = mp.Memory64List.unpack(self._content, offset, self)
            elif stream.StreamType == mp.streamType.MemoryInfoListStream:
                self.memoryinfolist = mp.MemoryInfoList.unpack(self._content, offset, self)
            elif stream.StreamType == mp.streamType.SystemInfoStream:
                self.systeminfo = mp.SystemInfo.unpack(self._content, offset, self)