code: def sub(self, s):
      for k, v in self.macros.items():
          s = s.replace(k, v)
      return s
  
imports: import sys, os
  from distutils.errors import DistutilsPlatformError
  from distutils.ccompiler import CCompiler
  from distutils import log
label_desc: Use image node_id 4 for calling the MacroExpander obj's underlying member method code with example usage: obj.sub(s) and returns: s