Shopify API: Delete Discounts And Price Rules

I'm using the Shopify Python library to work with my store's orders, discounts, etc. I'm writing some tests that involve creating and deleting price rules and discounts.

def test_get_discount(self):
    random_number_string = str(randint(0,10000)) 
    price_rule = shopify.PriceRule.create({
        'title': 'TEST-PRICERULE-' + random_number_string,
        'target_type': 'line_item',
        'target_selection': 'all',
        'allocation_method': 'across',
        'value_type': 'fixed_amount',
        'value': -1000,
        'once_per_customer': True,
        'customer_selection': 'all',
        'starts_at': datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    })
    discount = shopify.DiscountCode.create({
        'price_rule_id': price_rule.id,
        'code': 'TEST-DISCOUNT-' + random_number_string,
        'usage_count': 1,
        'value_type': 'fixed_amount',
        'value': -1000
    })
    fetched_price_rule = shopify_utils.get_discount_codes('TEST-PRICERULE-' + random_number_string)
    self.assertIsNotNone(fetched_price_rule)
    #deleted_discount = discount.destroy()
    #self.assertIsNone(deleted_discount)
    deleted_price_rule = price_rule.delete('discounts')
    self.assertIsNone(deleted_price_rule)

Everything up to deleting works properly. I'm also able to delete a discount with no problem, but when i try to delete a price rule, it errors out with the following:

deleted_price_rule = price_rule.delete()
TypeError: _instance_delete() missing 1 required positional argument: 'method_name'

I believe that it's asking me for the nested resource name, so I've tried passing things like discounts, discount_code, etc, but no luck. I see that pyactiveresouce is using that method_name to construct a url to delete the related resource, just don't know what their API looks like as it's not very well documented for cases like this.

When i do specify a (wrong) method name, I get this error:

pyactiveresource.connection.ClientError: Response(code=406, body="b''", headers={'Server': 'nginx', 'Date': 'Sun, 10 Sep 2017 00:57:28 GMT', 'Content-Type': 'application/json', 'Transfer-Encoding': 'chunked', 'Connection': 'close', 'X-Sorting-Hat-PodId': '23', 'X-Sorting-Hat-PodId-Cached': '0', 'X-Sorting-Hat-ShopId': '13486411', 'X-Sorting-Hat-Section': 'pod', 'X-Sorting-Hat-ShopId-Cached': '0', 'Referrer-Policy': 'origin-when-cross-origin', 'X-Frame-Options': 'DENY', 'X-ShopId': '13486411', 'X-ShardId': '23', 'X-Shopify-Shop-Api-Call-Limit': '3/40', 'HTTP_X_SHOPIFY_SHOP_API_CALL_LIMIT': '3/40', 'X-Stats-UserId': '0', 'X-Stats-ApiClientId': '1807529', 'X-Stats-ApiPermissionId': '62125531', 'Strict-Transport-Security': 'max-age=7776000', 'Content-Security-Policy': "default-src 'self' data: blob: 'unsafe-inline' 'unsafe-eval' https://* shopify-pos://*; block-all-mixed-content; child-src 'self' https://* shopify-pos://*; connect-src 'self' wss://* https://*; script-src https://cdn.shopify.com https://checkout.shopifycs.com https://js-agent.newrelic.com https://bam.nr-data.net https://dme0ih8comzn4.cloudfront.net https://api.stripe.com https://mpsnare.iesnare.com https://appcenter.intuit.com https://www.paypal.com https://maps.googleapis.com https://stats.g.doubleclick.net https://www.google-analytics.com https://visitors.shopify.com https://v.shopify.com https://widget.intercom.io https://js.intercomcdn.com 'self' 'unsafe-inline' 'unsafe-eval'; upgrade-insecure-requests; report-uri /csp-report?source%5Baction%5D=error_404&source%5Bapp%5D=Shopify&source%5Bcontroller%5D=admin%2Ferrors&source%5Bsection%5D=admin_api&source%5Buuid%5D=72550a71-d55b-4fb2-961f-f0447c1d04c6", 'X-Content-Type-Options': 'nosniff', 'X-Download-Options': 'noopen', 'X-Permitted-Cross-Domain-Policies': 'none', 'X-XSS-Protection': '1; mode=block; report=/xss-report?source%5Baction%5D=error_404&source%5Bapp%5D=Shopify&source%5Bcontroller%5D=admin%2Ferrors&source%5Bsection%5D=admin_api&source%5Buuid%5D=72550a71-d55b-4fb2-961f-f0447c1d04c6', 'X-Dc': 'ash,chi2', 'X-Request-ID': '72550a71-d55b-4fb2-961f-f0447c1d04c6'}, msg="Not Acceptable") 

Any ideas hugely appreciated!

As @Tim mentioned in his response, the destroy method worked for me and successfully deleted all children instances as well as parent instance.