# Buggy code
def ProcessSources(
    self,
    source_path_specs,
    storage_writer,
    resolver_context,
    processing_configuration,
    filter_find_specs=None,
    status_update_callback=None,
):
    """Processes the sources.

    Args:
      source_path_specs (list[dfvfs.PathSpec]): path specifications of
          the sources to process.
      storage_writer (StorageWriter): storage writer for a session storage.
      resolver_context (dfvfs.Context): resolver context.
      processing_configuration (ProcessingConfiguration): processing
          configuration.
      filter_find_specs (Optional[list[dfvfs.FindSpec]]): find specifications
          used in path specification extraction.
      status_update_callback (Optional[function]): callback function for status
          updates.

    Returns:
      ProcessingStatus: processing status.
    """
    parser_mediator = parsers_mediator.ParserMediator(
        storage_writer,
        self.knowledge_base,
        preferred_year=processing_configuration.preferred_year,
        resolver_context=resolver_context,
        temporary_directory=processing_configuration.temporary_directory,
    )

    parser_mediator.SetEventExtractionConfiguration(
        processing_configuration.event_extraction
    )

    parser_mediator.SetInputSourceConfiguration(processing_configuration.input_source)

    extraction_worker = worker.EventExtractionWorker(
        parser_filter_expression=(processing_configuration.parser_filter_expression)
    )

    extraction_worker.SetExtractionConfiguration(processing_configuration.extraction)

    self._status_update_callback = status_update_callback

    logging.debug("Processing started.")

    self._StartProfiling(extraction_worker)

    if self._serializers_profiler:
        storage_writer.SetSerializersProfiler(self._serializers_profiler)

    storage_writer.Open()
    storage_writer.WriteSessionStart()

    try:
        storage_writer.WritePreprocessingInformation(self.knowledge_base)

        self._ProcessSources(
            source_path_specs,
            extraction_worker,
            parser_mediator,
            storage_writer,
            filter_find_specs=filter_find_specs,
        )

    finally:
        storage_writer.WriteSessionCompletion(aborted=self._abort)

        storage_writer.Close()

        if self._serializers_profiler:
            storage_writer.SetSerializersProfiler(None)

        self._StopProfiling(extraction_worker)

    if self._abort:
        logging.debug("Processing aborted.")
        self._processing_status.aborted = True
    else:
        logging.debug("Processing completed.")

    self._status_update_callback = None

    return self._processing_status


# Traceback (AttributeError)
Traceback (most recent call last):
File "./tools/log2timeline.py", line 678, in <module>
if not Main():
File "./tools/log2timeline.py", line 664, in Main
tool.ProcessSources()
File "./tools/log2timeline.py", line 575, in ProcessSources
worker_memory_limit=self._worker_memory_limit)
File "/tmp/test/plaso/frontend/extraction_frontend.py", line 379, in ProcessSources
status_update_callback=status_update_callback)
File "/tmp/test/plaso/engine/single_process.py", line 330, in ProcessSources
storage_writer, filter_find_specs=filter_find_specs)
File "/tmp/test/plaso/engine/single_process.py", line 147, in _ProcessSources
extraction_worker, parser_mediator, event_source.path_spec)
File "/tmp/test/plaso/engine/single_process.py", line 77, in _ProcessPathSpec
if self._processing_configuration.debug_output:
AttributeError: 'NoneType' object has no attribute 'debug_output'

# Fixed code
def ProcessSources(
    self,
    source_path_specs,
    storage_writer,
    resolver_context,
    processing_configuration,
    filter_find_specs=None,
    status_update_callback=None,
):
    """Processes the sources.

    Args:
      source_path_specs (list[dfvfs.PathSpec]): path specifications of
          the sources to process.
      storage_writer (StorageWriter): storage writer for a session storage.
      resolver_context (dfvfs.Context): resolver context.
      processing_configuration (ProcessingConfiguration): processing
          configuration.
      filter_find_specs (Optional[list[dfvfs.FindSpec]]): find specifications
          used in path specification extraction.
      status_update_callback (Optional[function]): callback function for status
          updates.

    Returns:
      ProcessingStatus: processing status.
    """
    parser_mediator = parsers_mediator.ParserMediator(
        storage_writer,
        self.knowledge_base,
        preferred_year=processing_configuration.preferred_year,
        resolver_context=resolver_context,
        temporary_directory=processing_configuration.temporary_directory,
    )

    parser_mediator.SetEventExtractionConfiguration(
        processing_configuration.event_extraction
    )

    parser_mediator.SetInputSourceConfiguration(processing_configuration.input_source)

    extraction_worker = worker.EventExtractionWorker(
        parser_filter_expression=(processing_configuration.parser_filter_expression)
    )

    extraction_worker.SetExtractionConfiguration(processing_configuration.extraction)

    self._processing_configuration = processing_configuration
    self._status_update_callback = status_update_callback

    logging.debug("Processing started.")

    self._StartProfiling(extraction_worker)

    if self._serializers_profiler:
        storage_writer.SetSerializersProfiler(self._serializers_profiler)

    storage_writer.Open()
    storage_writer.WriteSessionStart()

    try:
        storage_writer.WritePreprocessingInformation(self.knowledge_base)

        self._ProcessSources(
            source_path_specs,
            extraction_worker,
            parser_mediator,
            storage_writer,
            filter_find_specs=filter_find_specs,
        )

    finally:
        storage_writer.WriteSessionCompletion(aborted=self._abort)

        storage_writer.Close()

        if self._serializers_profiler:
            storage_writer.SetSerializersProfiler(None)

        self._StopProfiling(extraction_worker)

    if self._abort:
        logging.debug("Processing aborted.")
        self._processing_status.aborted = True
    else:
        logging.debug("Processing completed.")

    self._processing_configuration = None
    self._status_update_callback = None

    return self._processing_status