The demo changed a default and compared it with an explicit keyword override. Here you will write a different default for a parcel label. The two supplied print calls let you compare the ordinary label and your chosen keyword override.
parcel_label a default mark="." and return name + mark.mark="!" as a keyword argument.Edit main.py, press Run to inspect the result, then Submit to check your change.
Add the default in the definition first; then name mark in the second call.