classes/fields/pick.php
public function register_related_object( $name, $label, $options = null ) {

		if ( empty( $name ) || empty( $label ) ) {
			return false;
		}

		$related_object = array(
			'label'         => $label,
			'group'         => 'Custom Relationships',
			'simple'        => true,
			'bidirectional' => false,
			'data'          => array(),
			'data_callback' => null,
		);

		$related_object = array_merge( $related_object, $options );

		self::$custom_related_objects[ $name ] = $related_object;

		return true;

	}
public function register_related_object( $name, $label, $options = null ) {

		if ( empty( $name ) || empty( $label ) ) {
			return false;
		}

		$related_object = array(
			'label'         => $label,
			'group'         => 'Custom Relationships',
			'simple'        => true,
			'bidirectional' => false,
			'data'          => array(),
			'data_callback' => null,
		);

		$related_object = array_merge( $related_object, $options );

		self::$custom_related_objects[ $name ] = $related_object;

		return true;

	}
public function register_related_object ( $ name , $ label , $ options = null ) { if ( empty ( $ name ) || empty ( $ label ) ) { return false ; } $ related_object = array ( 'label' => $ label , 'group' => 'Custom Relationships' , 'simple' => true , 'bidirectional' => false , 'data' => array ( ) , 'data_callback' => null , ) ; $ related_object = array_merge ( $ related_object , $ options ) ; self :: $ custom_related_objects [ $ name ] = $ related_object ; return true ; }
Register a related object.

@param string $name    Object name.
@param string $label   Object label.
@param array  $options Object options.

@return array|boolean Object array or false if unsuccessful
@since 2.3.0
Register a related object .