code: func shiftArray(a *Container) (*Container, bool) {
  	statsHit("shift/Array")
  	carry := false
  	aa := a.array()
  	output := make([]uint16, 0, len(aa))
  	for _, v := range aa {
  		if v+1 == 0 { // overflow
  			carry = true
  		} else {
  			output = append(output, v+1)
  		}
  	}
  	return NewContainerArray(output), carry
  }
docs: // shiftArray is an array-specific implementation of shift().