Retrieve the start, stop and step indices from the slice object slice,
assuming a sequence of length length. Treats indices greater than
length as errors.
Returns 0 on success and -1 on error with no exception set (unless one of
the indices was not None and failed to be converted to an integer,
in which case -1 is returned with an exception set).
You probably do not want to use this function. If you want to use slice
objects in versions of Python prior to 2.3, you would probably do well to
incorporate the source of PySlice_GetIndicesEx(), suitably renamed,
in the source of your extension.
Changed in version 2.5: This function used an int type for length and an
int * type for start, stop, and step. This might require
changes in your code for properly supporting 64-bit systems.