code: def mergeGraphs(targetGraph, addedGraph, incrementedNodeVal = 'count', incrementedEdgeVal = 'weight'):
      for addedNode, attribs in addedGraph.nodes(data = True):
          if incrementedNodeVal:
              try:
                  targetGraph.node[addedNode][incrementedNodeVal] += attribs[incrementedNodeVal]
              except KeyError:
                  targetGraph.add_node(addedNode, **attribs)
          else:
              if not targetGraph.has_node(addedNode):
                  targetGraph.add_node(addedNode, **attribs)
      for edgeNode1, edgeNode2, attribs in addedGraph.edges(data = True):
          if incrementedEdgeVal:
              try:
                  targetGraph.edges[edgeNode1, edgeNode2][incrementedEdgeVal] += attribs[incrementedEdgeVal]
              except KeyError:
                  targetGraph.add_edge(edgeNode1, edgeNode2, **attribs)
          else:
              if not targetGraph.Graph.has_edge(edgeNode1, edgeNode2):
                  targetGraph.add_edge(edgeNode1, edgeNode2, **attribs)