code: def get_all_edge_type(etype2files, symmetry):
      """get all edge type"""
      if symmetry:
          etype_list = []
          for etype in etype2files.keys():
              r_etype = get_inverse_etype(etype)
              etype_list.append(etype)
              if r_etype != etype:
                  etype_list.append(r_etype)
      else:
          etype_list = list(etype2files.keys())
  
      return etype_list
  
imports: import sys
  import datetime
  import os
  import yaml
  import random
  import shutil
  import six
  import warnings
  import glob
  from collections import defaultdict
  from pgl.utils.logger import log
label_desc: Use image node_id 2 for calling a global function with example usage: get_all_edge_type(etype2files, symmetry) and returns: etype_list