docs: def _parse_roles(self):
          """
          Generate a dictionary for configured roles from oslo_config.
  
          Due to limitations in ini format, it's necessary to specify
          roles in a flatter format than a standard dictionary. This
          function serves to transform these roles into a standard
          python dictionary.
          """
          roles = {}
          for keystone_role, flask_role in self.config.roles.items():
              roles.setdefault(flask_role, set()).add(keystone_role)
          return roles