code: def transform(self, tr_list, files):
          
          singular = False
          if not isinstance(files, list) and not isinstance(files, tuple):
              singular = True
              files = [files]
  
          for _find, _replace in tr_list:
              files = [opt.replace(_find, _replace) for opt in files]
  
          if singular:
              return files[0]
          else:
              return files
docs: replaces $tokens$ with values
          will be replaced with config rendering