TypeError: str() takes at most 1 argument (2 given)

[wlombeidad]

MKBRUTUS 1.0.2
Phyton 3.5.1
macOSX 10.11.3

ERROR 1: Sorry, Python 3.x is required to run this tool. Overrided changing IF statement!

ERROR 2:

[*] Starting bruteforce attack...

Traceback (most recent call last):
File "/library/python/mkbrutus.py", line 363, in
main()
File "/library/python/mkbrutus.py", line 329, in main
defaultcreds = apiros.login("admin", "")
File "/library/python/mkbrutus.py", line 103, in login
for repl, attrs in self.talk(["/login"]):
File "/library/python/mkbrutus.py", line 113, in talk
if self.writeSentence(words) == 0: return
File "/library/python/mkbrutus.py", line 132, in writeSentence
self.writeWord(w)
File "/library/python/mkbrutus.py", line 145, in writeWord
self.writeLen(len(w))
File "/library/python/mkbrutus.py", line 154, in writeLen
self.writeStr(chr(l))
File "/library/python/mkbrutus.py", line 212, in writeStr
r = self.sk.send(bytes(str[n:], 'UTF-8'))
TypeError: str() takes at most 1 argument (2 given)

No clue what to do next... Is it OS X?