code: function range(start, stop, step) {
  
    if (stop === undefined) return (0, _range2._range)(0, start, 1);
  
    if (step === undefined) return (0, _range2._range)(start, stop, 1);
  
    return (0, _range2._range)(start, stop, step);
  }
docs: Yields values in a range, separated by a fixed constant called step. If this
  step is negative, the range has to be given in reverse order, that is,
  largest value first, smallest value second. Both the starting value and the
  step value are optional. By default the starting value is <code>0</code>.
  The default for the step value is <code>1</code>.
  
  @param {Number} [start=0] - The starting value.
  @param {Number} stop - The stopping value.
  @param {Number} [step=1] - The step value.
  @returns {Iterator}