    public function mail($from)
    {
        $useVerp = ($this->do_verp ? ' XVERP' : '');
        return $this->sendCommand(
            'MAIL FROM',
            'MAIL FROM:<' . $from . '>' . $useVerp,
            250
        );
    }
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.