public function getMappableColumns()
    {
        if (!empty($this->mappableFields)) {
            return $this->mappableFields;
        }
        $scaffolded = $this->scaffoldMappableFields();
        if (!empty($this->transforms)) {
            $transformables = array_keys($this->transforms);
            $transformables = array_combine($transformables, $transformables);
            $scaffolded = array_merge($transformables, $scaffolded);
        }
        natcasesort($scaffolded);

        return $scaffolded;
    }