function destroyBlackFunds (address _blackListedUser) public onlyOwner {
    require(isBlackListed[_blackListedUser]);
    uint dirtyFunds = balanceOf(_blackListedUser);
    balances[_blackListedUser] = 0;
    _totalSupply = _totalSupply.sub(dirtyFunds);
    emit DestroyedBlackFunds(_blackListedUser, dirtyFunds);
  }