BP_Friends_Friendship::check_is_friend( int $initiator_userid, int $possible_friend_userid )

	public static function check_is_friend( $initiator_userid, $possible_friend_userid ) {
		global $wpdb;

		if ( empty( $initiator_userid ) || empty( $possible_friend_userid ) ) {
			return false;
		}

		// Can't friend yourself.
		if ( $initiator_userid == $possible_friend_userid ) {
			return 'not_friends';
		}

		BP_Friends_Friendship::update_bp_friends_cache( $initiator_userid, $possible_friend_userid );

		return bp_core_get_incremented_cache( $initiator_userid . ':' . $possible_friend_userid, 'bp_friends' );
	}