Python 3: If ``s`` is an instance of ``text_type``, return
    ``s.encode('ascii')``, otherwise return ``str(s, 'ascii', 'strict')``

    Python 2: If ``s`` is an instance of ``text_type``, return
    ``s.encode('ascii')``, otherwise return ``str(s)``

def ascii_native_(s):
    '''
    Python 3: If ``s`` is an instance of ``text_type``, return
    ``s.encode('ascii')``, otherwise return ``str(s, 'ascii', 'strict')``

    Python 2: If ``s`` is an instance of ``text_type``, return
    ``s.encode('ascii')``, otherwise return ``str(s)``
    '''
    if isinstance(s, text_type):
        s = s.encode('ascii')

    return str(s, 'ascii', 'strict') if PY3 else s