public function has($key)
    {
        $key = $this->getScalarKey($key);
        return isset($this->list[$key]);
    }
public function has($key)
    {
        $key = $this->getScalarKey($key);
        return isset($this->list[$key]);
    }
public function has ( $ key ) { $ key = $ this -> getScalarKey ( $ key ) ; return isset ( $ this -> list [ $ key ] ) ; }
Check if item in map

@param mixed $key
@return bool
Check if item in map