NameError: global name “unicode” is not defined – in Python 3

I am trying to use a Python package called bidi. In a module in this package (algorithm.py) there are some lines that give me error, although it is part of the package.

Here are the lines:

# utf-8 ? we need unicode
if isinstance(unicode_or_str, unicode):
    text = unicode_or_str
    decoded = False
else:
    text = unicode_or_str.decode(encoding)
    decoded = True

and here is the error message:

Traceback (most recent call last):
  File "<pyshell#25>", line 1, in <module>
    bidi_text = get_display(reshaped_text)
  File "C:Python33libsite-packagespython_bidi-0.3.4-py3.3.eggidialgorithm.py",   line 602, in get_display
    if isinstance(unicode_or_str, unicode):
NameError: global name "unicode" is not defined

How should I re-write this part of the code so it works in Python3? Also if anyone have used bidi package with Python 3 please let me know if they have found similar problems or not. I appreciate your help.