code: def get_graph(cls, response):
  		
  		if cls.is_graph(response):	# single graph object
  			return response
  
  		if hasattr(response, '__getitem__'):	# indexable tuple
  			if len(response) > 0 and \
  			   cls.is_graph(response[0]):	# graph object
  				return response[0]
docs: Given a Flask response, find the rdflib Graph