public function isLoopback(): bool
    {
        if ($this->is_loopback === null) {
            $this->is_loopback = $this->isIn(static::$loopback_range);
        }

        return $this->is_loopback;
    }
public function isLoopback(): bool
    {
        if ($this->is_loopback === null) {
            $this->is_loopback = $this->isIn(static::$loopback_range);
        }

        return $this->is_loopback;
    }
public function isLoopback ( ) : bool { if ( $ this -> is_loopback === null ) { $ this -> is_loopback = $ this -> isIn ( static :: $ loopback_range ) ; } return $ this -> is_loopback ; }
Return true if the address is within the loopback range.

@return bool
Return true if the address is within the loopback range .