public function has(string $key): bool
    {
        $key = $this->prepareKey($key);
        return Arr::has($this->properties, $key);
    }
public function has(string $key): bool
    {
        $key = $this->prepareKey($key);
        return Arr::has($this->properties, $key);
    }
public function has ( string $ key ) : bool { $ key = $ this -> prepareKey ( $ key ) ; return Arr :: has ( $ this -> properties , $ key ) ; }
Check if key exist.

@param string $key Uses dot notation.
@return bool
Check if key exist .