code: function require(...names) {
  		const unknown = names.filter(name => !options[name]);
  		if (unknown.length > 0) {
  			throw new MrmUndefinedOption(`Required config options are missed: ${unknown.join(', ')}.`, {
  				unknown,
  			});
  		}
  		return config;
  	}
docs: Mark config options as required.
  
  @param {string[]} names...
  @return {Object} this