code: def get_module_source_path(modname, basename=None):
      
      srcpath = get_module_path(modname)
      parentdir = osp.join(srcpath, osp.pardir)
      if osp.isfile(parentdir):
          # Parent directory is not a directory but the 'library.zip' file:
          # this is either a py2exe or a cx_Freeze distribution
          srcpath = osp.abspath(osp.join(osp.join(parentdir, osp.pardir),
                                         modname))
      if basename is not None:
          srcpath = osp.abspath(osp.join(srcpath, basename))
      return srcpath
docs: Return module *modname* source path
      If *basename* is specified, return *modname.basename* path where 
      *modname* is a package containing the module *basename*
      
      *basename* is a filename (not a module name), so it must include the
      file extension: .py or .pyw
      
      Handles py2exe/cx_Freeze distributions