In a shell:
import errors
raise errors.ValidationError("foo")
---------------------------------------------------------------------------
ValidationError Traceback (most recent call last)
<ipython-input-11-464b5e215eb8> in <module>()
----> 1 raise errors.ValidationError("foo")
ValidationError:
This is because the error classes do not call the super constructor in their constructor overwrites. Do you have a reason to not call the super constructors there? I have fixed this locally so I can see what is actually going on when, e.g. a ValidationError was raised. When you are interested I can open a pull request with my fix.