bucket.upload_from_stream('tester', "hello! this is data")
with open('tester.txt', 'w') as file:
    bucket.download_to_stream_by_name('tester', file)

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "gridfs/__init__.py", line 691, in download_to_stream_by_name
    destination.write(gout)
TypeError: expected a character buffer object