code: function applyArg(request_url, template_part, actual_part) {
  	if (typeof(request_url.args) === "undefined") {
  		request_url.args = {};
  	}
  
  	if (typeof request_url.args !== "object") {
  		throw new Error("The request url's args have already been defined as a " + typeof request_url.args + " and we expected an object. For safety we are throwing this error instead of overwriting your existing data. Please use a different field name in your code");
  	}
  
  	request_url.args[template_part] = actual_part;
  }
docs: Assigns a value to the parsed request urls args parameter
  
  @param {object} request_url - The parsed url object
  @param {string} template_part - The template variable
  @param {*} actual_part - The url value