title: TypeError: object() takes no parameters
body: <p>My code generates the following error: <code>TypeError: object() takes no parameters</code></p>
  
  <pre><code>class Graph(object):
      def vertices(self):
          return list(self.__graph_dict.keys())
  
  if __name__ == "__main__":
  
      g = { "a" : ["d"],
            "b" : ["c"],
            "c" : ["b", "c", "d", "e"],
            "d" : ["a", "c"],
            "e" : ["c"],
            "f" : []
          }
  
      graph = Graph(g)
  
      print("Vertices of graph:")
      print(graph.vertices())
  </code></pre>
  
  <p>Is there a way I can solve this?</p>