code: def __init__(self, graph_data):
      self.name = "Paddle Graph"
      self.version = graph_data["version"]
      self.all_nodes = {
          node["name"]: node for node in graph_data["nodes"]
      }
      self.all_vars = {var["name"]: var for var in graph_data["vars"]}
      self.all_edges = {
          (edge["from_node"], edge["to_node"]): edge
          for edge in graph_data["edges"]
      }
      self.visible_maps = {
          node["name"]: (True if not node["children_node"] else False)
          for node in graph_data["nodes"]
      }
      root_node = self.all_nodes["/"]
      for child_name in root_node["children_node"]:
          self.visible_maps[child_name] = True
  
imports: from collections import defaultdict
  from collections import deque
label_desc: Use image node_id 1 to create a new Model object  with example: obj = Model(graph_data)