code: def template(colors, input_file, output_file=None):
      
      template_data = util.read_file_raw(input_file)
  
      try:
          template_data = "".join(template_data).format(**colors)
      except ValueError:
          logging.error("Syntax error in template file '%s'.", input_file)
          return
  
      util.save_file(template_data, output_file)
docs: Read template file, substitute markers and
         save the file elsewhere.