class_docstr: Implementation of SubGraph in pgl.
  
  Subgraph is inherit from :code:`Graph`. The best way to construct subgraph
  is to use :code:`Graph.subgraph` methods to generate Subgraph object.
  
  Args:
      num_nodes: number of nodes in a graph
      edges: list of (u, v) tuples
      node_feat (optional): a dict of numpy array as node features
      edge_feat (optional): a dict of numpy array as edge features (should
                              have consistent order with edges)
      reindex: A dictionary that maps parent graph node id to subgraph node id.
class_docstr_tok: ["Implementation","of","SubGraph","in","pgl",".","Subgraph","is","inherit","from",":","code",":","`","Graph","`",".","The","best","way","to","construct","subgraph","is","to","use",":","code",":","`","Graph.subgraph","`","methods","to","generate","Subgraph","object",".","Args",":","num_nodes",":","number","of","nodes","in","a","graph","edges",":","list","of","(","u",",","v",")","tuples","node_feat","(","optional",")",":","a","dict","of","numpy","array","as","node","features","edge_feat","(","optional",")",":","a","dict","of","numpy","array","as","edge","features","(","should","have","consistent","order","with","edges",")","reindex",":","A","dictionary","that","maps","parent","graph","node","id","to","subgraph","node","id","."]
docstr: Map the given subgraph node id to parent graph id.
  
  Args:
      nodes: A list of nodes in this subgraph.
  
  Return:
      A list of node ids in parent graph.
code: def reindex_to_parrent_nodes(self, nodes):
      """Map the given subgraph node id to parent graph id.
  
      Args:
          nodes: A list of nodes in this subgraph.
  
      Return:
          A list of node ids in parent graph.
      """
      return graph_kernel.map_nodes(nodes, self._to_reindex)
  
imports: import os
  import numpy
  import pickle
  import time
  import pgl.graph_kernel
  from collections import defaultdict
label_desc: Use image node_id 3 for calling the SubGraph obj's underlying member method code with example usage: obj.reindex_to_parrent_nodes(nodes) and returns: graph_kernel