Apply suggestions from code review

Co-authored-by: Ankush Menat <ankushmenat@gmail.com>
diff --git a/erpnext/accounts/doctype/subscription/subscription.py b/erpnext/accounts/doctype/subscription/subscription.py
index f19bae7..175710c 100644
--- a/erpnext/accounts/doctype/subscription/subscription.py
+++ b/erpnext/accounts/doctype/subscription/subscription.py
@@ -384,7 +384,7 @@
 		invoice.flags.ignore_mandatory = True
 		invoice.save()
 
-		if self.submit_invoice == 1:
+		if self.submit_invoice:
 			invoice.submit()
 
 		return invoice