commentjson: Unicode error in commentjson v0.7.2 in python2.7 environment

After upgrading commentjson to v0.7.2 getting bellows problem, you know codebase is same.

with io.open("some json file path", "r", encoding="utf-8") as fp:
    commentjson.loads(fp.read())

File "/home/nazrul/.cache/buildout/eggs/commentjson-0.7.2-py2.7.egg/commentjson/commentjson.py", line 73, in loads
    text = six.text_type(text, 'utf-8')
TypeError: decoding Unicode is not supported