code: def put_function(self, fn):
          
          if fn.function_name in self._functions:
              self._functions[fn.function_name]['latest'] = fn
          else:
              self._functions[fn.function_name] = {
                  'latest': fn,
                  'versions': [],
                  'alias': weakref.WeakValueDictionary()
              }
  
          self._arns[fn.function_arn] = fn
docs: :param fn: Function
          :type fn: LambdaFunction