code: def _norm_vars(var_str):
      return _var_pattern.sub("@scalar", var_str)
  
file_path: mars/mars/optimization/logical/tileable/tests/test_arithmetic_query.py
imports: import re
  import numpy
  import pandas
  from .....None import dataframe
  from .....None import execute, fetch
  from .....core import enter_mode, TileableGraph, TileableGraphBuilder
  from .....dataframe.base.eval import DataFrameEval
  from ..None import optimize
label_desc: Use image node_id 1 for calling a global function with example usage: _norm_vars(var_str) and returns: _var_pattern