code: protected String substituteParametersInTemplate(final FunctionTemplate template, final Map<String, String> params) {
          String ret = template.getFiles().get("function.java");
          for (final Map.Entry<String, String> entry : params.entrySet()) {
              ret = ret.replace(String.format("$%s$", entry.getKey()), entry.getValue());
          }
          return ret;
      }
docs: region Substitute parameters