"TypeError: expected string or buffer" stemming from BeautifulSoup

I am trying to scrape data from yelp and put it into a .csv file using urllib, beautifulsoup, and pandas. I am getting several errors and I am not sure what to do.

I have reviewed all the similar questions I could find online but none of them seem to be the same issue.

This is what error I get at runtime:

Traceback (most recent call last):
File "/Users/sydney/PycharmProjects/yelpdata/venv/yelp.py", line 7, in <module>
page_soup = bs.BeautifulSoup(source, 'html.parser')
File "/Users/sydney/PycharmProjects/yelpdata/venv/lib/python2.7/site- 
packages/bs4/__init__.py", line 310, in __init__
markup, from_encoding, exclude_encodings=exclude_encodings)):
File "/Users/sydney/PycharmProjects/yelpdata/venv/lib/python2.7/site- 
packages/bs4/builder/_htmlparser.py", line 248, in prepare_markup
exclude_encodings=exclude_encodings)
File "/Users/sydney/PycharmProjects/yelpdata/venv/lib/python2.7/site-packages/bs4/dammit.py", 
line 395, in __init__
for encoding in self.detector.encodings:
File "/Users/sydney/PycharmProjects/yelpdata/venv/lib/python2.7/site-packages/bs4/dammit.py", 
line 278, in encodings
self.markup, self.is_html)
File "/Users/sydney/PycharmProjects/yelpdata/venv/lib/python2.7/site-packages/bs4/dammit.py", 
line 343, in find_declared_encoding
declared_encoding_match = xml_re.search(markup, endpos=xml_endpos)
TypeError: expected string or buffer

This is my python file (linked to GitHub)