code: def slice_index(self, *slice_dims, **kwargs):
          
          return tuple(slice(l, u, 1) for l, u in zip(
              self.dim_lower_extent(*slice_dims, single=False),
              self.dim_upper_extent(*slice_dims, single=False)))
docs: Returns a tuple of slices, each slice equal to the
          slice(lower_extent, upper_extent, 1) of the dimensions
          supplied in slice_dims. If the dimension is integer d,
          slice(0, d, 1) will be used instead of the lower and upper extents
  
          .. code-block:: python
  
              A = np.ones(ntime, na)
              idx = cube.slice_index('ntime','na', 3)
              A[idx].sum()
              ntime, na, components = cube.slice_index('ntime', 'na', 3)
              A[ntime, na, components].sum()
  
          Parameters
          ----------
          *slice_dims : tuple
              Tuple of dimensions for which slice
              objects should be returned.
  
  
          Returns
          -------
              tuple
                  Tuple of :code:`slice(lower,upper,1)` objects