code: def preparse(output_format):
      
      try:
          return templating.preparse(output_format, lambda path: os.path.join(config.config_dir, "templates", path))
      except ImportError as exc:
          if "tempita" in str(exc):
              raise error.UserError("To be able to use Tempita templates, install the 'tempita' package (%s)\n"
                  "    Possibly USING THE FOLLOWING COMMAND:\n"
                  "        %s/easy_install tempita" % (exc, os.path.dirname(sys.executable)))
          raise
      except IOError as exc:
          raise error.LoggableError("Cannot read template: {}".format(exc))
docs: Do any special processing of a template, and return the result.