private function maybe_register_cache_events() {

		$key = get_class( $this );
		$key .= "-{$this->attribute}";

		if ( isset( $this->registered_cache_events[ $key ] ) ) {
			return;
		}

		$this->register_cache_events();

		$this->registered_cache_events[ $key ] = true;
	}
private function maybe_register_cache_events() {

		$key = get_class( $this );
		$key .= "-{$this->attribute}";

		if ( isset( $this->registered_cache_events[ $key ] ) ) {
			return;
		}

		$this->register_cache_events();

		$this->registered_cache_events[ $key ] = true;
	}
private function maybe_register_cache_events ( ) { $ key = get_class ( $ this ) ; $ key .= "-{$this->attribute}" ; if ( isset ( $ this -> registered_cache_events [ $ key ] ) ) { return ; } $ this -> register_cache_events ( ) ; $ this -> registered_cache_events [ $ key ] = true ; }
Maybe register cache events.

Cache events should only be registered once per relation.

@since 2.o
Maybe register cache events .