python examples: another importer

* Fixed a similar type of bug with the non-protonmail importer.

lang/python/examples/howto/import-keys-hkp.py

@@ -45,7 +45,10 @@ else:
 
 try:
     keys = server.search(pattern)
+    if keys is not None:
         print("Found {0} key(s).".format(len(keys)))
+    else:
+        pass
 except Exception as e:
     keys = []
     for logrus in pattern.split():
@@ -56,7 +59,8 @@ except Exception as e:
         keys.append(key[0])
     print("Found {0} key(s).".format(len(keys)))
 
-for key in keys:
+if keys is not None:
+    for key in keys:
         import_result = c.key_import(key.key_blob)
         results.append(import_result)