Error

[d0ubl3puls4r]

Hello, when executing the sqlmate python command, the following error appears:

root@kali:~/sqlmate# python sqlmate
Traceback (most recent call last):
File "sqlmate", line 4, in
from bs4 import BeautifulSoup
File "/usr/local/lib/python2.7/dist-packages/bs4/init.py", line 30, in
from .builder import builder_registry, ParserRejectedMarkup
File "/usr/local/lib/python2.7/dist-packages/bs4/builder/init.py", line 314, in
from . import _html5lib
File "/usr/local/lib/python2.7/dist-packages/bs4/builder/_html5lib.py", line 70, in
class TreeBuilderForHtml5lib(html5lib.treebuilders._base.TreeBuilder):
AttributeError: 'module' object has no attribute '_base'

I already did the pip install -r requirements.txt command, but still the problem continued, how to solve this problem?
Thank you very much in advance.