Convert persistence collector output to downloadable rdfvalues.

def Parse(self, persistence, knowledge_base, download_pathtype):
    """Convert persistence collector output to downloadable rdfvalues."""
    pathspecs = []

    if isinstance(persistence, rdf_client.OSXServiceInformation):
      if persistence.program:
        pathspecs = rdf_paths.PathSpec(
            path=persistence.program, pathtype=download_pathtype)
      elif persistence.args:
        pathspecs = rdf_paths.PathSpec(
            path=persistence.args[0], pathtype=download_pathtype)

    for pathspec in pathspecs:
      yield rdf_standard.PersistenceFile(pathspec=pathspec)