code: def _graph_add_edge(self, cfg_node, src_node, src_jumpkind, src_ins_addr, src_stmt_idx):
          
  
          if src_node is None:
              self.graph.add_node(cfg_node)
          else:
              self.graph.add_edge(src_node, cfg_node, jumpkind=src_jumpkind, ins_addr=src_ins_addr,
                                  stmt_idx=src_stmt_idx)
docs: Add edge between nodes, or add node if entry point
  
          :param CFGNode cfg_node: node which is jumped to
          :param CFGNode src_node: node which is jumped from none if entry point
          :param str src_jumpkind: what type of jump the edge takes
          :param int or str src_stmt_idx: source statements ID
          :return: None