How to make shipping cost free Magento 2 for a custom shipping method

Found it, In case someone needs this :

In my shipping.php file there is a function called collectRates which is reponsible for returning the shipping rates, I added

    if($request->getBaseSubtotalInclTax()>100){
        $method->setPrice(0);
    }

Basically If the total is more than 100$ I make the shipping price free, It would be better to make the 100$ a dynamic value which can be changed in the shipping method settings I will do it later.

this is my collectRates Function in the end:

 * @param RateRequest $request

 * @return bool|Result

 */

public function collectRates(RateRequest $request)

{
    if (!$this->getConfigFlag('active')) {
        return false;
    }

    /** @var MagentoShippingModelRateResult $result */

    $result = $this->_rateResultFactory->create();

    /** @var MagentoQuoteModelQuoteAddressRateResultMethod $method */

    $method = $this->_rateMethodFactory->create();
    $method->setCarrier($this->_code);
    $method->setCarrierTitle($this->getConfigData('title'));
    $method->setMethod($this->_code);
    $method->setMethodTitle($this->getConfigData('name'));
    $amount = $this->getShippingPrice();
    $method->setPrice($amount);
    if($request->getBaseSubtotalInclTax()>100){
        $method->setPrice(0);
    }
    $method->setCost($amount);
    $result->append($method);
    return $result;

}