def non_form_errors(self):
        if self._non_form_errors is not None:
            return self._non_form_errors
        return self.error_class()
Return the new dictionary of coordinate variables given by merging in
dataset/ETHPy150Open dcramer/django-compositepks/django/forms/formsets.py/BaseFormSet.non_form_errors--crossover with--dataset/ETHPy150Open pydata/xarray/xarray/core/merge.py/merge_dataarray_coords