Internal/KillSwitch.php
public function addAddress($address)
    {
        if (!$this->hasAddress($address)) {
            $this->data->addresses[] = $address;
        }

        return $this;
    }
public function addAddress($address)
    {
        if (!$this->hasAddress($address)) {
            $this->data->addresses[] = $address;
        }

        return $this;
    }
@param string $address

@return $this