code: def del_key(self, key, key_to_delete):
          "Delete the `key_to_delete` for the record found with `key`."
          v = self.get(key)
          if key_to_delete in v:
              del v[key_to_delete]
              self.set(key, vf del_key(self, key, key_to_delete):
          "Delete the `key_to_delete` for the record found with `key`."
          v = self.get(key)
          if key_to_delete in v:
              del v[key_to_delete]
              self.set(key, v)
docs: Delete the `key_to_delete` for the record found with `key`.