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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 mr_dim_ind(self):
 """Get the correct index of the MR dimension in the cube slice."""

        mr_dim_ind = self._cube.mr_dim_ind
        if self._cube.ndim == 3:
            if isinstance(mr_dim_ind, int):
                if mr_dim_ind == 0:
                    # If only the 0th dimension of a 3D is an MR, the sliced
                    # don't actuall have the MR... Thus return None.
                    return None
                return mr_dim_ind - 1
            elif isinstance(mr_dim_ind, tuple):
                # If MR dimension index is a tuple, that means that the cube
                # (only a 3D one if it reached this path) has 2 MR dimensions.
                # If any of those is 0 ind dimension we don't need to include
                # in the slice dimension (because the slice doesn't see the tab
                # that it's on). If it's 1st and 2nd dimension, then subtract 1
                # from those, and present them as 0th and 1st dimension of the
                # slice. This can happend e.g. in a CAT x MR x MR cube (which
                # renders MR x MR slices).
                mr_dim_ind = tuple(i - 1 for i in mr_dim_ind if i)
                return mr_dim_ind if len(mr_dim_ind) > 1 else mr_dim_ind[0]

        return mr_dim_ind