public function keep_memory( $keep_memory = true ) {

		$prev = $this->keep_memory;

		$this->keep_memory = $keep_memory;

		return $prev;
	}
public function keep_memory( $keep_memory = true ) {

		$prev = $this->keep_memory;

		$this->keep_memory = $keep_memory;

		return $prev;
	}
public function keep_memory ( $ keep_memory = true ) { $ prev = $ this -> keep_memory ; $ this -> keep_memory = $ keep_memory ; return $ prev ; }
Configure the collection to keep memory of added or removed elements.

@since 2.0

@param bool $keep_memory

@return bool
Configure the collection to keep memory of added or removed elements .