feat: python typing (#646)

* feat: python typing

* Update noxfile.py

Co-authored-by: IlyaFaer <[email protected]>
Co-authored-by: Astha Mohta <[email protected]>

Author: 3 people

google/cloud/spanner_v1/__init__.py

@@ -18,7 +18,7 @@
 
 import pkg_resources
 
-__version__ = pkg_resources.get_distribution("google-cloud-spanner").version
+__version__: str = pkg_resources.get_distribution("google-cloud-spanner").version
 
 from .services.spanner import SpannerClient
 from .types.commit_response import CommitResponse

google/cloud/spanner_v1/instance.py

@@ -17,6 +17,7 @@
 import google.api_core.operation
 from google.api_core.exceptions import InvalidArgument
 import re
+import typing
 
 from google.protobuf.empty_pb2 import Empty
 from google.protobuf.field_mask_pb2 import FieldMask
@@ -42,7 +43,7 @@
 DEFAULT_NODE_COUNT = 1
 PROCESSING_UNITS_PER_NODE = 1000
 
-_OPERATION_METADATA_MESSAGES = (
+_OPERATION_METADATA_MESSAGES: typing.Tuple = (
     backup.Backup,
     backup.CreateBackupMetadata,
     backup.CopyBackupMetadata,

google/cloud/spanner_v1/snapshot.py

@@ -102,7 +102,7 @@ class _SnapshotBase(_SessionWrapper):
     """
 
     _multi_use = False
-    _read_only = True
+    _read_only: bool = True
     _transaction_id = None
     _read_request_count = 0
     _execute_sql_count = 0