Google-cloud-python: google cloud storage - Traceback while calling list_blobs on bucket

[bmoscon]

OS: MacOS Mojave
Python: 3.7.3

google versions:
google-api-core==1.11.1
google-auth==1.6.3
google-cloud-core==1.0.1
google-cloud-storage==1.16.0
google-resumable-media==0.3.2
googleapis-common-protos==1.6.0

code:

from google.cloud.storage import Client 

client = Client()
files = client.get_bucket(BUCKET).list_blobs(key)
for f in files:
    print(f.name)

traceback:

~/example.py
15 files = client.get_bucket(BUCKET).list_blobs(key)
---> 16 for f in files:
17 print(f.name)
18

~/python3.7/site-packages/google/api_core/page_iterator.py in _items_iter(self)
202 def _items_iter(self):
203 """Iterator for each item returned."""
--> 204 for page in self._page_iter(increment=False):
205 for item in page:
206 self.num_results += 1

~/python3.7/site-packages/google/api_core/page_iterator.py in _page_iter(self, increment)
233 Page: each page of items from the API.
234 """
--> 235 page = self._next_page()
236 while page is not None:
237 self.page_number += 1

~/python3.7/site-packages/google/api_core/page_iterator.py in _next_page(self)
359 """
360 if self._has_next_page():
--> 361 response = self._get_next_page_response()
362 items = response.get(self._items_key, ())
363 page = Page(self, items, self.item_to_value)

~/python3.7/site-packages/google/api_core/page_iterator.py in _get_next_page_response(self)
406 ValueError: If the HTTP method is not GET or POST.
407 """
--> 408 params = self._get_query_params()
409 if self._HTTP_METHOD == "GET":
410 return self.api_request(

~/python3.7/site-packages/google/api_core/page_iterator.py in _get_query_params(self)
393 result[self._PAGE_TOKEN] = self.next_page_token
394 if self.max_results is not None:
--> 395 result[self._MAX_RESULTS] = self.max_results - self.num_results
396 result.update(self.extra_params)
397 return result

TypeError: unsupported operand type(s) for -: 'str' and 'int'

[bmoscon]

the issue was on my end, while list_blobs doesn't complain about taking an arg, I should have used the prefix kwarg. oops!