code: def getStartNodes(fdefs,calls):
      '''Return a list of nodes in fdefs that have no inbound edges'''
      s=[]
      for source in fdefs:
          for fn in fdefs[source]:
              inboundEdges=False
              for call in calls:
                  if call.target==fn:
                      inboundEdges=True
              if not inboundEdges:
                  s.append(fn)
      return f getStartNodes(fdefs,calls):
      '''Return a list of nodes in fdefs that have no inbound edges'''
      s=[]
      for source in fdefs:
          for fn in fdefs[source]:
              inboundEdges=False
              for call in calls:
                  if call.target==fn:
                      inboundEdges=True
              if not inboundEdges:
                  s.append(fn)
      return s
docs: Return a list of nodes in fdefs that have no inbound edges