<NA>
<NA>
function increaseAllowance(address spender, uint256 addedValue)
        public
        returns (bool)
    {
        _allowance[msg.sender][spender] = _allowance[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowance[msg.sender][spender]);
        return true;
    }
/**
 * @dev Increase the amount of tokens that an owner has allowed to a spender.
 * This method should be used instead of approve() to avoid the double approval vulnerability
 * described above.
 * @param spender The address which will spend the funds.
 * @param addedValue The amount of tokens to increase the allowance by.
 */