code: function nthArg(n) {
        n = toInteger(n);
        return baseRest(function(args) {
          return baseNth(args, n);
        });
      }
docs: Creates a function that gets the argument at index `n`. If `n` is negative,
  the nth argument from the end is returned.
  
  @static
  @memberOf _
  @since 4.0.0
  @category Util
  @param {number} [n=0] The index of the argument to return.
  @returns {Function} Returns the new pass-thru function.
  @example
  
  var func = _.nthArg(1);
  func('a', 'b', 'c', 'd');
  // => 'b'
  
  var func = _.nthArg(-2);
  func('a', 'b', 'c', 'd');
  // => 'c'