brownie VS openzeppelin-contracts

Check out Brownie if you are familiar with python https://github.com/eth-brownie/brownie

If you are going to use Brownie in this challenge, in your virtual environment, go ahead and install Brownie, after you installed it, create a new folder called nft and inside it run the following command:

Python and Brownie ETH, or any smart contract framework

Web3.py and Brownie setup, testing and deployment

One more advice - try executing the swaps in javascript/nodejs (https://github.com/ethers-io/ethers.js/) or python (https://github.com/eth-brownie/brownie) first, can be easier to learn. Then move it into a smart contract.

Check out ETH-Brownie first of all, you're going to love it if you're a Python guy. The docs are great.

For python backend development, I really like this tool, eth-brownie.

Take a look at Brownie https://github.com/eth-brownie/brownie

For someone coming from Python, Vyper would be easier to learn. There is some learning material to help you start, but for more advanced concepts it might be harder to find. And some of Ethereum tools (for security, for monitoring) are built for Solidity, but in the last couple of months some of them started to include more Vyper support. And to test your contracts, and a basis dev environnement for Vyper, Brownie (https://github.com/eth-brownie/brownie) might be the best choice, since it's Python based

ETH-Brownie

Lets look the events of Open Zeppelin’s ERC20 token contract:

ERC-777 is difficult to implement properly, due to its susceptibility to different forms of attack(opens in a new tab). It is recommended to use ERC-20 instead. This page remains as a historical archive.

This depends if you're writing a contract from scratch or using existing code. If you're making something new, then yes (recommend not to use THE most recent available, always better to go with tried and tested). For existing projects, never try to override the solidity version. This may be a pain with "@" imports - ideally everyone should specify the library version (e.g. https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/token/ERC20/ERC20.sol).