import codecs
import io


def mojibake(s):
    # makes an illegal double-utf encoding, to simulate mojibake
    return s.encode('utf8').decode('latin1').encode('utf8')


def unmojibake(b):
    # decodes the illegal mojibake
    return b.decode('utf8').encode('latin1').decode('utf8')


def make_stream(b):
    i = io.BytesIO(b)
    utf8 = codecs.lookup("utf-8")
    latin1 = codecs.lookup("latin1")
    # set up recoder to decode as utf8 and then encode as latin1
    return codecs.StreamRecoder(
        i,
        latin1.encode,
        utf8.decode,     # won't be used, we do not write
        utf8.streamreader,
        latin1.streamwriter  # won't be used, we do not write
    )

s = 'Hello \u2013my\u2013 World' # 'Hello –my– World'
b = mojibake(s)
assert unmojibake(b) == s

read = make_stream(b).read()
read1 = make_stream(b).read1()

print('original', b)
print('read()  ', read)
print('read1() ', read1)

# expected result: read == read1
# actual result: read1 == b (the original bytes we put into the io)