public function has($key): bool
    {
        return $this->exists($key) && null !== $this->attributes[$key];
    }
public function has($key): bool
    {
        return $this->exists($key) && null !== $this->attributes[$key];
    }
public function has ( $ key ) : bool { return $ this -> exists ( $ key ) && null !== $ this -> attributes [ $ key ] ; }
Checks if an a key is present and not null.

@param  string|array $key
@return bool
Checks if an a key is present and not null .