diff --git a/Lib/ssl.py b/Lib/ssl.py
index ab7a49b..df39592 100644
--- a/Lib/ssl.py
+++ b/Lib/ssl.py
@@ -410,7 +410,8 @@ class SSLContext(_SSLContext):
             if encoding == "x509_asn":
                 if trust is True or purpose.oid in trust:
                     certs.extend(cert)
-        self.load_verify_locations(cadata=certs)
+        if certs:
+            self.load_verify_locations(cadata=certs)
         return certs
 
     def load_default_certs(self, purpose=Purpose.SERVER_AUTH):