Issue with byte array caused by Python version 3.8.5

[deng113jie]

No description provided.

[deng113jie]

Unittest report error when running test_session with python version 3.8.5:

FAIL: test_create_then_load_categorical (tests.test_session.TestCreateThenLoadBetweenSessionsNew)

Traceback (most recent call last):
File "/home/jie/ExeTera/tests/test_session.py", line 103, in test_create_then_load_categorical
self.assertDictEqual({1: b'a', 2: b'b'}, f.keys)
AssertionError: {1: b'a', 2: b'b'} != {1: 'a', 2: 'b'}

• {1: b'a', 2: b'b'}
  ? - -

• {1: 'a', 2: 'b'}

======================================================================
FAIL: test_create_then_load_categorical (tests.test_session.TestCreateThenLoadBetweenSessionsOld)

Traceback (most recent call last):
File "/home/jie/ExeTera/tests/test_session.py", line 57, in test_create_then_load_categorical
self.assertDictEqual({1: b'a', 2: b'b'}, f.keys)
AssertionError: {1: b'a', 2: b'b'} != {1: 'a', 2: 'b'}

• {1: b'a', 2: b'b'}
  ? - -

• {1: 'a', 2: 'b'}

---

Ran 50 tests in 15.759s

FAILED (failures=2)
(base) jie@debian:~/ExeTera$ python --version
Python 3.8.5

Related code:
def test_create_then_load_categorical(self):
bio = BytesIO()
contents = [1, 2, 1, 2]
with session.Session() as s:
with h5py.File(bio, 'w') as src:
df = src.create_group('df')
f = s.create_categorical(df, 'foo', 'int8', {b'a': 1, b'b': 2})
f.data.write(np.array(contents))

    with session.Session() as s:
        with h5py.File(bio, 'r') as src:
            f = s.get(src['df']['foo'])
            self.assertListEqual(contents, f.data[:].tolist())
            **self.assertDictEqual({1: b'a', 2: b'b'}, f.keys)**

Seems python zip function put the byte array into string, so b'a' is not equals to 'a' hence unittest report error. This is ok when running python 3.7.5