protected function describeConversion(IdProperty $newProp, IdProperty $oldProp = null)
    {
        if ($oldProp) {
            $new  = $this->labelFromProp($newProp);
            $old  = $this->labelFromProp($oldProp);
            $desc = sprintf('Converting to %s from %s.', $new, $old);
        } else {
            $new  = $this->labelFromProp($newProp);
            $desc = sprintf('Converting to %s.', $new);
        }

        $this->climate()->comment($desc);

        return $this;
    }