'Some widgets require a modified rendering context, if they contain angular directives.'

def get_context(self, name, value, attrs):

    context = super(NgWidgetMixin, self).get_context(name, value, attrs)
    if callable(getattr(self._field, u'update_widget_rendering_context', None)):
        self._field.update_widget_rendering_context(context)
    return context
