def _InitializeParserObjects(self, parser_filter_expression=None):
    """Initializes the parser objects.

    Args:
      parser_filter_expression (Optional[str]): the parser filter expression,
          None represents all parsers and plugins.

          The parser filter expression is a comma separated value string that
          denotes a list of parser names to include and/or exclude. Each entry
          can have the value of:

          * An exact match of a list of parsers, or a preset (see
            data/presets.yaml for the list of predefined presets).
          * A name of a single parser (case insensitive), e.g. msiecf.
          * A glob name for a single parser, e.g. '*msie*' (case insensitive).
    """
    self._formats_with_signatures, non_sigscan_parser_names = (
        parsers_manager.ParsersManager.GetFormatsWithSignatures(
            parser_filter_expression=parser_filter_expression))

    self._non_sigscan_parser_names = []
    for parser_name in non_sigscan_parser_names:
      if parser_name not in ('filestat', 'usnjrnl'):
        self._non_sigscan_parser_names.append(parser_name)

    self._file_scanner = parsers_manager.ParsersManager.CreateSignatureScanner(
        self._formats_with_signatures)

    self._parsers = parsers_manager.ParsersManager.GetParserObjects(
        parser_filter_expression=parser_filter_expression)

    active_parser_names = ', '.join(sorted(self._parsers.keys()))
    logger.debug('Active parsers: {0:s}'.format(active_parser_names))

    self._filestat_parser = self._parsers.get('filestat', None)
    if 'filestat' in self._parsers:
      del self._parsers['filestat']

    self._mft_parser = self._parsers.get('mft', None)

    self._usnjrnl_parser = self._parsers.get('usnjrnl', None)
    if 'usnjrnl' in self._parsers:
      del self._parsers['usnjrnl']
Initializes the parser objects.

    Args:
      parser_filter_expression (Optional[str]): the parser filter expression,
          None represents all parsers and plugins.

          The parser filter expression is a comma separated value string that
          denotes a list of parser names to include and/or exclude. Each entry
          can have the value of:

          * An exact match of a list of parsers, or a preset (see
            data/presets.yaml for the list of predefined presets).
          * A name of a single parser (case insensitive), e.g. msiecf.
          * A glob name for a single parser, e.g. '*msie*' (case insensitive).