mypy: Annotate utils.get_device_size

Add annotations for parameters of this method.

Change-Id: I3149e0067f97d373333e0901e49725401fc6c068

os_brick/initiator/connectors/nvmeof.py

@@ -1195,7 +1195,11 @@ class NVMeOFConnector(base.BaseLinuxConnector):
             LOG.info('Wait 5 seconds and return whatever size is present')
             time.sleep(5)
 
-        return utils.get_device_size(self, device_path)
+        size = utils.get_device_size(self, device_path)
+        if size is None:
+            raise exception.BrickException(
+                'get_device_size returned non-numeric size')
+        return size
 
     # #######  RAID methods ########
 

os_brick/utils.py

@@ -25,6 +25,7 @@ from oslo_concurrency import processutils
 from oslo_log import log as logging
 from oslo_utils import strutils
 
+from os_brick import executor
 from os_brick.i18n import _
 from os_brick.privileged import nvmeof as priv_nvme
 from os_brick.privileged import rootwrap as priv_rootwrap
@@ -400,7 +401,7 @@ def connect_volume_undo_prepare_result(
     return decorator
 
 
-def get_device_size(executor, device):
+def get_device_size(executor: executor.Executor, device: str) -> Optional[int]:
     """Get the size in bytes of a volume."""
     (out, _err) = executor._execute('blockdev', '--getsize64',
                                     device, run_as_root=True,