In Python, when slicing a list, the step parameter determines the interval between elements in the slice.
A step of 0, however, is not allowed and will raise a 'ValueError'.
This is because a step of 0 would imply a non-progressing slice, meaning no movement through the list, which is illogical for the operation.
Therefore, setting the step to 0 in list slicing is an invalid operation and will immediately result in an error, preventing any slicing from occurring.
In such case it does not even matter what other indices like start and stop are set to.