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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _create_dim_scales(self):
 """Create all necessary HDF5 dimension scale."""

        dim_order = self._dim_order.maps[0]
        for dim in sorted(dim_order, key=lambda d: dim_order[d]):
            if dim not in self._h5group:
                size = self._current_dim_sizes[dim]
                kwargs = {}
                if self._dim_sizes[dim] is None:
                    kwargs["maxshape"] = (None,)
                self._h5group.create_dataset(
                    name=dim, shape=(size,), dtype='S1', **kwargs)

            h5ds = self._h5group[dim]
            h5ds.attrs['_Netcdf4Dimid'] = dim_order[dim]

            if len(h5ds.shape) > 1:
                dims = self._variables[dim].dimensions
                coord_ids = np.array([dim_order[d] for d in dims], 'int32')
                h5ds.attrs['_Netcdf4Coordinates'] = coord_ids

            scale_name = dim if dim in self.variables else NOT_A_VARIABLE
            h5ds.dims.create_scale(h5ds, scale_name)

        for subgroup in self.groups.values():
            subgroup._create_dim_scales()