diff --git a/ironic_python_agent/extensions/standby.py b/ironic_python_agent/extensions/standby.py
index 42aa9b868..c7db614b4 100644
--- a/ironic_python_agent/extensions/standby.py
+++ b/ironic_python_agent/extensions/standby.py
@@ -706,7 +706,7 @@ def _validate_image_info(ext, image_info=None, **kwargs):
             msg = 'Image is missing \'{}\' field.'.format(field)
             raise errors.InvalidCommandParamsError(msg)
 
-    if type(image_info['urls']) != list or not image_info['urls']:
+    if not isinstance(image_info['urls'], list) or not image_info['urls']:
         raise errors.InvalidCommandParamsError(
             'Image \'urls\' must be a list with at least one element.')
 
diff --git a/tox.ini b/tox.ini
index 53bf77ebc..3f0beaf62 100644
--- a/tox.ini
+++ b/tox.ini
@@ -37,11 +37,11 @@ commands = stestr run {posargs}
 
 [testenv:pep8]
 deps =
-    hacking~=6.0.0 # Apache-2.0
-    bashate>=0.5.1 # Apache-2.0
-    flake8-import-order>=0.17.1 # LGPLv3
+    hacking~=6.1.0 # Apache-2.0
+    bashate~=2.1.0 # Apache-2.0
+    flake8-import-order~=0.18.0 # LGPLv3
     pycodestyle>=2.0.0,<3.0.0 # MIT
-    doc8>=0.8.1 # Apache-2.0
+    doc8~=1.1.0 # Apache-2.0
 allowlist_externals = bash
                       {toxinidir}/tools/run_bashate.sh
 commands =