contract ABC_Token {
  mapping(address => uint) balances;
  event Transfer(address indexed from, 
                address indexed to, 
                uint value);
  
  function transfer(address to, uint amount) 
    external returns (bool) {
      require(balances[msg.sender] >= amount);
      // ... execution
  }
}

interface ILiquidityPool {
  function addLiquidity(
    uint256 tokenAmount, 
    uint256 ethAmount
  ) external payable returns (uint256);
  
  function removeLiquidity(
    uint256 liquidity
  ) external returns (uint, uint);
}

const connectWallet = async () => {
  if (window.ethereum) {
    const accounts = await window.ethereum
      .request({ 
        method: 'eth_requestAccounts' 
      });
    setAccount(accounts[0]);
    // Initialize Web3 Provider
  }
}