private function formatBelongsToMany()
    {
        // Return if there are no relationships of that type
        if (!isset($this->relationships['belongsToMany']) || empty($this->relationships['belongsToMany'])) {
            return $this;
        }

        // Iterate relationships
        foreach ($this->relationships['belongsToMany'] as $join) {
            $this->records = array_map(function ($record) use ($join) {
                foreach ($record as $key => $value) {
                    if ($key === 'concat_' . $join['alias']) {
                        $record[$join['alias']] = ($value)? explode(',', $value) : [];
                        unset($record[$key]);
                    }
                }
                return $record;
            }, $this->records);
        }

        // Return model instance
        return $this;
    }