Deprecated since 3.15. Accepting the + and / characters is now deprecated.
Decode bytes using the URL- and filesystem-safe Base64 alphabet.
Argument s is a bytes-like object or ASCII string to decode. The result
is returned as a bytes object. A binascii.Error is raised if the input
is incorrectly padded. Characters that are not in the URL-safe base-64
alphabet, and are not a plus '+' or slash '/', are discarded prior to the
padding check.
If padded is false, padding in input is not required.
The alphabet uses '-' instead of '+' and '_' instead of '/'.