traits.php

<?php

interface SettingsInterface {


	public function get_setting( $key );


	public function set_setting( $key, $value );


}

trait SettingsTrait {


	protected $settings = [];


	abstract public function get_url();


	public function init_settings() {

		wp_remote_get( $this->get_url() );

		// set $this->settings, etc...

		return $this;
	}


	public function get_setting( $key ) {

		return isset( $this->settings[ $key ] ) ? $this->settings[ $key ] : null;
	}


	public function set_setting( $key, $value ) {

		$this->settings[ $key ] = $value;
	}


}

class Advanced_Matching_Settings implements SettingsInterface {


	use SettingsTrait;


	public $pixel_id;


	public function set_pixel_id( $pixel_id ) {

		$this->pixel_id = $pixel_id;

		return $this;
	}


	public function get_pixel_id() {

		return $this->pixel_id;
	}


	public function get_url() {

		return 'https://connect.facebook.net/signals/config/json/' . $this->get_pixel_id();
	}


	public function is_enabled() {

		return (bool) $this->get_setting( 'enableAutomaticMatching' );
	}


}

$settings = ( new Advanced_Matching_Settings() )->set_pixel_id( '1234' )->init_settings();

echo $settings->is_enabled();