code: func (b *Bittrex) Withdraw(address, currency string, quantity decimal.Decimal) (withdrawUuid string, err error) {
  	r, err := b.client.do("GET", fmt.Sprintf("account/withdraw?currency=%s&quantity=%s&address=%s", strings.ToUpper(currency), quantity, address), "", true)
  	if err != nil {
  		return
  	}
  	var response jsonResponse
  	if err = json.Unmarshal(r, &response); err != nil {
  		return
  	}
  	if err = handleErr(response); err != nil {
  		return
  	}
  	var u Uuid
  	err = json.Unmarshal(response.Result, &u)
  	withdrawUuid = u.Id
  	return
  }
docs: // Withdraw is used to withdraw funds from your account.
  // address string the address where to send the funds.
  // currency string literal for the currency (ie. BTC)
  // quantity decimal.Decimal the quantity of coins to withdraw