Decode the Base16 encoded bytes-like object or ASCII string s.
Optional casefold is a flag specifying whether a lowercase alphabet is
acceptable as input. For security purposes, the default is False.
ignorechars should be a byte string containing characters to ignore
from the input.
The result is returned as a bytes object. A binascii.Error is raised if
s is incorrectly padded or if there are non-alphabet characters present
in the input.