def dtypes(self) -> Frozen[Hashable, np.dtype]:
        """Mapping from coordinate names to dtypes.

        Cannot be modified directly, but is updated when adding new variables.

        See Also
        --------
        Dataset.dtypes
        """
        return Frozen(
            {
                n: v.dtype
                for n, v in self._data._variables.items()
                if n in self._data._coord_names
            }
        )
Mapping from coordinate names to dtypes.

        Cannot be modified directly, but is updated when adding new variables.

        See Also
        --------
        Dataset.dtypes
        
xarray/core/coordinates.py