docs: function makeErrFromCode(statusCode) {
      // assert!
      assert.number(statusCode, 'statusCode');
      assert.equal(statusCode >= 400, true);
  
      // drop the first arg
      var args = _.drop(_.toArray(arguments));
      var name = helpers.errNameFromCode(statusCode);
  
      var ErrCtor = httpErrors[name];
  
      // assert constructor was found
      assert.func(ErrCtor);
  
      // pass every other arg down to constructor
      return makeInstance(ErrCtor, makeErrFromCode, args);
  }