The random function on solidity, read more in Vietnamese: https://nhatky.dev/2022/10/20/minh-dang-dung-ham-solidity-random-number-nhu-nay

TestRandom.sol

// SPDX-License-Identifier: MIT

pragma solidity 0.8.0;

import "./libs/zeppelin/token/BEP20/IBEP20.sol";

interface ILPToken is IBEP20 {
  function getReserves() external view returns (uint, uint);
}

contract TestRandom {
  string private seed;
  ILPToken[] private lpTokens;

  event Success(bool success);
  
  modifier notContract() {
    require(msg.sender.code.length == 0, "Contract not allowed");
    _;
  }

  constructor(string memory _seed, address _token1, address _token2, address _token3) {
    seed = _seed;
    lpTokens.push(ILPToken(_token1));
    lpTokens.push(ILPToken(_token2));
    lpTokens.push(ILPToken(_token3));
  }

  function foo() external notContract() {
    uint8 random = _genRandomNumberInRange(seed, _getDexSeed(), 0, 99);
    emit Success(random < 7);
  }

  function _getDexSeed() private view returns (uint) {
    (uint reserve00, uint reserve10) = lpTokens[0].getReserves();
    (uint reserve01, uint reserve11) = lpTokens[1].getReserves();
    (uint reserve02, uint reserve12) = lpTokens[2].getReserves();
    return reserve00 + reserve10 + reserve01 + reserve11 + reserve02 + reserve12;
  }

  function _genRandomNumberInRange(string memory _seed, uint _dexRandomSeed, uint _from, uint _to) private view returns (uint8) {
    require(_to > _from, 'TestRandom: Invalid range');
    uint randomNumber = uint(
      keccak256(
        abi.encodePacked(
          keccak256(
            abi.encodePacked(
              block.number,
              block.difficulty,
              block.timestamp,
              msg.sender,
              _seed,
              _dexRandomSeed
            )
          )
        )
      )
    ) % (_to - _from + 1);
    return uint8(randomNumber + _from);
  }
}