Ok, 2 issues that I have managed to correct in this code and get it working:
1) The following line of code makes a list, that why the GraphAPI object is not able to identify a valid access token:
session['token'] = [token.itervalues().next()]
2) The following line of code gives an error stating that 'dict' is not callable. This is because the returned variable is a dictionary and, in order to be returned as a view, one must first transform it into a string:
return graph.get_object("me")