code: def normalize_dataflow(dataflow):
      var_dict = {}
      i = 0
      normalized_dataflow = []
      for item in dataflow:
          var_name = item[0]
          relationship = item[2]
          par_vars_name_list = item[3]
          for name in par_vars_name_list:
              if name not in var_dict:
                  var_dict[name] = "var_" + str(i)
                  i += 1
          if var_name not in var_dict:
              var_dict[var_name] = "var_" + str(i)
              i += 1
          normalized_dataflow.append(
              (
                  var_dict[var_name],
                  relationship,
                  [var_dict[x] for x in par_vars_name_list],
              )
          )
      return normalized_dataflow
  
file_path: codet5/CodeT5/evaluator/CodeBLEU/dataflow_match.py
imports: from CodeT5.evaluator.CodeBLEU.parser import DFG_python, DFG_java, DFG_ruby, DFG_go, DFG_php, DFG_javascript, DFG_csharp
  from CodeT5.evaluator.CodeBLEU.parser import remove_comments_and_docstrings, tree_to_token_index, index_to_code_token
  from tree_sitter import Language, Parser
  import os
label_desc: Use image node_id 5 for calling a global function with example usage: normalize_dataflow(dataflow) and returns: normalized_dataflow