def get_installed_pypackages():
    return {p.project_name.lower(): p for p in pkg_resources.working_set}
def _restore_vars(v_list, t_list):
  """Restore variables in v_list from t_list."""
  ops = []
  for v, t in zip(v_list, t_list):
    ops.append(v.assign(t))
  return ops