About slices in Python

Question

1. Is there any difference between mylist[:] and mylist[::]?
2. What's the rationale for mylist[::0] to raise an error since negative steps are allowed?

Answer 1

1. No. Both result in slice(None, None, None).

2. Positive strides go forwards. Negative strides go backwards. Zero strides go... nowhere? How exactly would that work? An infinite sequence of a single value?

Answer 2

No difference between mylist[:] and mylist[::]

mylist[::0]

This implies from starting index to last index without any step, don't know in what world it would be possible.