code: def _Extract(
        self, source_path_specs, destination_path, output_writer,
        skip_duplicates=True):
      
      output_writer.Write('Extracting file entries.\n')
      path_spec_generator = self._path_spec_extractor.ExtractPathSpecs(
          source_path_specs, resolver_context=self._resolver_context)
  
      for path_spec in path_spec_generator:
        self._ExtractFileEntry(
            path_spec, destination_path, output_writer,
            skip_duplicates=skip_duplicates)
docs: Extracts files.
  
      Args:
        source_path_specs (list[dfvfs.PathSpec]): path specifications to extract.
        destination_path (str): path where the extracted files should be stored.
        output_writer (CLIOutputWriter): output writer.
        skip_duplicates (Optional[bool]): True if files with duplicate content
            should be skipped.