code: def remove_configurable(self, configurable_class, name):
          
          configurable_class_name = configurable_class.__name__.lower()
  
          logger.info("Removing %s: '%s'", configurable_class_name, name)
  
          registry = self.registry_for(configurable_class)
  
          if name not in registry:
              logger.warn(
                  "Tried to remove unknown active %s: '%s'",
                  configurable_class_name, name
              )
              return
  
          hook = self.hook_for(configurable_class, action="remove")
          if not hook:
              registry.pop(name)
              return
  
          def done(f):
              try:
                  f.result()
                  registry.pop(name)
              except Exception:
                  logger.exception("Error removing configurable '%s'", name)
  
          self.work_pool.submit(hook, name).add_done_callback(done)
docs: Callback fired when a configurable instance is removed.
  
          Looks up the existing configurable in the proper "registry" and
          removes it.
  
          If a method named "on_<configurable classname>_remove" is defined it
          is called via the work pooland passed the configurable's name.
  
          If the removed configurable is not present, a warning is given and no
          further action is taken.