code: def sub(self, s):
      for k, v in self.macros.items():
          s = s.replace(k, v)
      return s
  
imports: import sys
  import os
  import warnings
  from .errors import DistutilsExecError, DistutilsPlatformError, CompileError, LibError, LinkError
  from .ccompiler import CCompiler, gen_lib_options
  from ._log 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