code: def find_subclass(base: type, name: str) -> type:
      
      class_candidates = [klass
                          for klass in all_subclasses(base)
                          if klass.__name__ == name
                          ]
      if len(class_candidates) == 0:
          raise RuntimeError("No \"{0}\" subclass of \"{1}\".".format(base.__name__, name))
      elif len(class_candidates) > 1:
          raise RuntimeError("Multiple \"{0}\" subclasses of \"{1}\".".format(base.__name__, name))
      return class_candidates[0]
docs: Find a named subclass of a base class.
  
      Uses only the class name without namespace.