Add an exception if timeout and dns_resolver are both passed

Author: JoshData

email_validator/deliverability.py

@@ -31,6 +31,8 @@ def validate_email_deliverability(domain: str, domain_i18n: str, timeout: Option
             timeout = DEFAULT_TIMEOUT
         dns_resolver = dns.resolver.get_default_resolver()
         dns_resolver.lifetime = timeout
+    elif timeout is not None:
+        raise ValueError("It's not valid to pass both timeout and dns_resolver.")
 
     deliverability_info: Dict[str, Any] = {}
 

email_validator/validate_email.py

@@ -40,7 +40,7 @@ def validate_email(
         test_environment = TEST_ENVIRONMENT
     if globally_deliverable is None:
         globally_deliverable = GLOBALLY_DELIVERABLE
-    if timeout is None:
+    if timeout is None and dns_resolver is None:
         timeout = DEFAULT_TIMEOUT
 
     # Allow email to be a str or bytes instance. If bytes,