docs: def get_subjects_with_equal_or_higher_perm(self, perm_str):
          """
      Args:
        perm_str : str
          Permission, ``read``, ``write`` or ``changePermission``.
  
      Returns:
        set of str : Subj that have perm equal or higher than ``perm_str``.
  
        Since the lowest permission a subject can have is ``read``, passing ``read``
        will return all subjects.
      """
          self._assert_valid_permission(perm_str)
          return {
              s
              for p in self._equal_or_higher_perm(perm_str)
              for s in self._perm_dict.get(p, set())
          }