def _merge_inplace(self, other):
        """For use with in-place binary arithmetic."""
        if other is None:
            yield
        else:
            # don't include indexes in prioritized, because we didn't align
            # first and we want indexes to be checked
            prioritized = {
                k: (v, None)
                for k, v in self.variables.items()
                if k not in self.xindexes
            }
            variables, indexes = merge_coordinates_without_align(
                [self, other], prioritized
            )
            yield
            self._update_coords(variables, indexes)
For use with in-place binary arithmetic.
xarray/core/coordinates.py