Error executing python_script since 0.95 update (TypeError: %d)

Hello i have updated hassio this morning and since then one of my python script is not working with this error in the log:

Error executing script: %d format: a number is required, not NoneType
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/python_script/__init__.py", line 159, in execute
    exec(compiled.code, restricted_globals, local)
  File "summary.py", line 174, in <module>
TypeError: %d format: a number is required, not NoneType

The line it refers on my .py file is this one:

        time = "%02d:%02d" % (dt.hour, dt.minute)

Does anyone have an idea ?

Thanks.