func: function fundVesting(uint256 _totalTokens) public onlyOwner {
      require(totalTokens == 0, "Vesting already funded");
      require(token.allowance(owner, address(this)) == _totalTokens);
      totalTokens = _totalTokens;
      token.transferFrom(owner, address(this), totalTokens);
      emit VestingFunded(_totalTokens);
    }