public function update( $data ) {

		$updated_values = array();

		foreach ( $data as $key => $value ) {
			$method = 'set_' . $key;

			if ( method_exists( $this, $method ) ) {
				$updated_value = $this->$method( $value );

				$updated_values[ $key ] = $updated_value;

			}
		}

		return $updated_values;

	}