code: function rotateLeft (a, amount) {
                      if(!(a instanceof Array)) return a;
                      return libs.array.rotate(a, 'left', amount);
                  }
docs: Rotates the array left the specified number of times.
  This is useful if trying to create a circular queue.
  @param {Array} a The Array object to operate on.
  @param {Number=} [amount=1] The number of times to rotate the array left.
  @return {Array<*>} The current array, rotated left.
  @function