src/properties/class-papi-property-relationship.php
public function get_sort_option( $post_id ) {
		$slug = $this->html_id( 'sort_option' );
		$slug = str_replace( '][', '_', $slug );
		$slug = str_replace( '[', '_', $slug );
		$slug = str_replace( ']', '', $slug );

		return papi_data_get( $post_id, $slug, $this->get_meta_type() );
	}
public function get_sort_option( $post_id ) {
		$slug = $this->html_id( 'sort_option' );
		$slug = str_replace( '][', '_', $slug );
		$slug = str_replace( '[', '_', $slug );
		$slug = str_replace( ']', '', $slug );

		return papi_data_get( $post_id, $slug, $this->get_meta_type() );
	}
Get sort option value.

@param  int $post_id

@return string