code: def _cull_redundant_about(obj):
      
      about_val = obj.get('@about')
      if about_val:
          id_val = obj.get('@id')
          if id_val and (('#' + id_val) == about_val):
              del obj['@about']
docs: Removes the @about key from the `obj` dict if that value refers to the
      dict's '@id'