public function delete(string $key): self
    {
        unset($this->data[$key]);
        unset($this->session[$key]);
        return $this;
    }
public function delete(string $key): self
    {
        unset($this->data[$key]);
        unset($this->session[$key]);
        return $this;
    }
public function delete ( string $ key ) : self { unset ( $ this -> data [ $ key ] ) ; unset ( $ this -> session [ $ key ] ) ; return $ this ; }
Remove specified key

@param string $key Key
@return  Flash
Remove specified key