public function has($key)
    {
        if(array_key_exists($key, $this->aliases) || array_key_exists($key, $this->resolved)) {
            return true;
        } else {
            return false;
        }
    }
public function has($key)
    {
        if(array_key_exists($key, $this->aliases) || array_key_exists($key, $this->resolved)) {
            return true;
        } else {
            return false;
        }
    }
public function has ( $ key ) { if ( array_key_exists ( $ key , $ this -> aliases ) || array_key_exists ( $ key , $ this -> resolved ) ) { return true ; } else { return false ; } }
Check a key is already exists.

@param string $key

@return bool
Check a key is already exists .