Incomplete Token Implementation: No Supply Mechanism
The `FourERC20` contract, as provided, is an incomplete ERC-20 implementation. It lacks a constructor to call the internal `_init` function to set `_name` and `_symbol`. More critically, it does not implement any public minting mechanism (e.g., a `_mint` call in the constructor for initial supply, or a public `mint` function) or a burning mechanism. As a result, if deployed directly, the token would have an empty name, symbol, and a `totalSupply` of zero, making it non-functional as a standard ERC-20 token.