code: def make_srcdir_list(self,exclude_dirs):
          
          srcdir_list = []
          for topdir in self.topdirs:
              srcdir_list.append(topdir)
              srcdir_list += self.recursive_dir_list(topdir,exclude_dirs)
          return srcdir_list
docs: Like os.walk, except that:
          a) directories listed in exclude_dir are excluded with all
            their subdirectories
          b) absolute paths are returned