If you are writing pytests for v0.10 of cairo and you see that error you may be using an `invoke()` method to call your contract like:


`contract.yourFunc(1000).invoke()`


Make sure you change that to:


`contract.yourFunc(1000).execute()`


and you should be good


ㅤ
_This answer was originally posted on [Triality](https://triality.org/question/1179)_

When running my python tests I get:


 NotImplementedError: Invoking through an account contract is not supported yet, please use execute() instead.


 Has anyone seen this problem and know of a solution?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/1179)_

Cairo Testing Error

I'm aware of starknet having a common--and unsafe--keccak library. Either way, I was wondering if there's a way to mimic the behavior of solidity's 
```
keccak256(abi.encode(parameters))
```
Thank you very much.

Is there a Cairo equivalent to Keccak256(abi.encode(parameters))?


Hello! This is day 16 of the 17 days of the Cairo Challenge. In this exercise it is required to submit your first StarkNet contract. When you try to make it, you get an error:

```solidity
Error: code:20:1: Unsupported %lang directive. Are you using the correct compiler?
%lang starknet
^************^
```

Can you show your solution to [playground](https://www.cairo-lang.org/playground/) exercise “StarkNet contract” and also send a link to your contract, and a screenshot where you use your `add` method?

```solidity
// [StarkNet](https://starkware.co/product/starknet/) is a permissionless decentralized ZK-Rollup operating
// as an L2 network over Ethereum, where any dApp can achieve
// unlimited scale for its computation, without compromising
// Ethereum's composability and security.
//
// This is a simple StarkNet contract.
// Note that you won't be able to use the playground to compile and run it,
// but you can deploy it on the [StarkNet Planets Alpha network](https://medium.com/starkware/starknet-planets-alpha-on-ropsten-e7494929cb95)!
//
// 1. Click on "Deploy" to deploy the contract.
//    For more information on how to write Cairo contracts see the
//    ["Hello StarkNet" tutorial](https://cairo-lang.org/docs/hello_starknet).
// 2. Click on the contract address in the output pane to open
//    [Voyager](https://goerli.voyager.online/) - the StarkNet block explorer.
// 3. Wait for the page to load the information
//    (it may take a few minutes until a block is created).
// 4. In the "STATE" tab, you can call the "add()" transaction.

// The "%lang" directive declares this code as a StarkNet contract.
%lang starknet

@view
func add(x: felt, y: felt) -> (res: felt) {
    return (res=x + y);
}
```

---

> Answers to this question are a part of the ✨ 17 days of Cairo Lang with Playground & Newton. ✨
> 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How to submit a StarkNet contract?

**I want to put a disconnect button in my dapp, does anyone know how to do this on the frontend?**

anyone know how to disconnect the connected wallet on the frontend with starknetjs or another way?


My ABIs will be same right? In UI I am assuming I wont have to make any changes

Hello! This is day 17 of the 17 days of the Cairo Challenge. In this challenge I want to ask you [install](https://www.cairo-lang.org/docs/quickstart.html) Cairo and try to launch your first program. What have you implemented as your first Cairo language program?

**Step 1**
```solidity
// 1. Make sure that you installed dev packages on your device
sudo apt install -y libgmp3-dev // Linux
brew install gmp // Mac OS
```
**Step 2**
```solidity
// 2. Install Cairo using Python virtual environment
python3.9 -m venv ~/cairo_venv
source ~/cairo_venv/bin/activate
pip3 install ecdsa fastecdsa sympy;
pip3 install cairo-lang;
```
**Step 3**
```bash
// 3. Make sure you have python 3.9. Because Cairo was tested with python3.9. To make it work with python3.6, you will have to install contextvars:
pip3 install contextvars
```
**Step 4**
```python
// 4. Write your program
// Create a file, named hello.cairo, with the following lines:
 
func main() {
		// edit me: you can add here any output, best program wins the challenge
    ret;
}

```solidity
//5. Compile your program
cairo-compile hello.cairo --output hello_compiled.json
```
**Last step**
```solidity

//6. Run:
cairo-run \
  --program=hello_compiled.json --print_output \
  --print_info --relocate_prints

//7. Debug:
//You can open the Cairo tracer by providing the --tracer flag to cairo-run. Then open it at http://localhost:8100/.
```
If you have questions, create them on Newton and we will help!

---
> Answers to this question are a part of the ✨ 17 days of Cairo Lang with Playground & Newton. ✨
> 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How to install Cairo v0.10.0 on my device?

How can I test on multi-chain with both Starknet and Ethereum?


ApeWorX: How can I test on multi-chain with both Starknet and Ethereum?

Looking to call the approve and transfer functions for an erc-20 in the same transaction. Thoughts on how to do this?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/1218)_

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