This is almost certainly because of this backwards-incompatible change in Django 2.1:
- Support for
Widget.render()methods without the
rendererargument is removed.
You may have subclassed
django.forms.widgets.Widget in your code, or in the code of one of your dependencies. The code may look like this:
from django.forms import widgets class ExampleWidget(widgets.Widget): def render(self, name, value, attrs=None): # ...
You need to fix the method signature of
render, so that it looks like this:
def render(self, name, value, attrs=None, renderer=None):
Have a look at the source code of
widgets.Widget if you want to check.