Separate files, registry keys, grep matches.

def _SeparateTypes(self, metadata_value_pairs):
    """Separate files, registry keys, grep matches."""
    registry_pairs = []
    file_pairs = []
    match_pairs = []
    for metadata, result in metadata_value_pairs:
      if (result.stat_entry.pathspec.pathtype ==
          rdf_paths.PathSpec.PathType.REGISTRY):
        registry_pairs.append((metadata, result.stat_entry))
      else:
        file_pairs.append((metadata, result))

      match_pairs.extend([(metadata, match) for match in result.matches])

    return registry_pairs, file_pairs, match_pairs