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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 _calculate_correct_axis_for_cube(self, axis):
 """Return correct axis for cube, based on ndim. If cube has 3 dimensions, increase axis by 1. This will translate the default 0 (cols direction) and 1 (rows direction) to actual 1 (cols direction) and 2 (rows direction). This is needed because the 0th dimension of the 3D cube is only used to slice across. The actual margins need to be calculated for each slice separately, and since they're implemented as an ndarray, the direction needs to be increased by one. For the value of `None`, don't modify the axis parameter. :param axis: 0, 1, or None. Axis that will be passed to self._cube methods. If the cube is 3D, the axis is typically increased by 1, to represent correct measure direction. :returns: int or None, representing the updated axis to pass to cube """


        if self._cube.ndim < 3:
            if self.ca_as_0th and axis is None:
                # Special case for CA slices (in multitables). In this case,
                # we need to calculate a measurement across CA categories
                # dimension (and not across items, because it's not
                # allowed). The value for the axis parameter of None, would
                # imply both cat and items dimensions, and we don't want that.
                return 1
            return axis

        # Expected usage of the 'axis' parameter from CubeSlice is 0, 1, or
        # None. CrunchCube handles all other logic. The only 'smart' thing
        # about the handling here, is that the axes are increased for 3D cubes.
        # This way the 3Dness is hidden from the user and he still sees 2D
        # crosstabs, with col and row axes (0 and 1), which are transformed to
        # corresponding numbers in case of 3D cubes (namely 1 and 2). In the
        # case of None, we need to analyze across all valid dimensions, and the
        # CrunchCube takes care of that (no need to update axis if it's None).
        # If the user provides a tuple, it's considered that he "knows" what
        # he's doing, and the axis argument is not updated in this case.
        if isinstance(axis, int):
            axis += 1
        return axis