fix tests

Author: mgyucht

tests/databricks/sdk/service/jsonmarshallv2.py

@@ -11,7 +11,7 @@
 from google.protobuf.timestamp_pb2 import Timestamp
 
 from databricks.sdk.common.types.fieldmask import FieldMask
-from databricks.sdk.service._internal import (_enum, _from_dict,
+from databricks.sdk.service._internal import (_duration, _enum, _from_dict,
                                               _repeated_dict, _repeated_enum)
 
 _LOG = logging.getLogger("databricks.sdk")