def _ipython_key_completions_(self) -> list[str]:
        """Provide method for the key-autocompletions in IPython.
        See https://ipython.readthedocs.io/en/stable/config/integrating.html#tab-completion
        For the details.
        """
        items = {
            item
            for source in self._item_sources
            for item in source
            if isinstance(item, str)
        }
        return list(items)
Provide method for the key-autocompletions in IPython.
        See https://ipython.readthedocs.io/en/stable/config/integrating.html#tab-completion
        For the details.
        
xarray/core/common.py