Fix settting of http host header field

Author: hackermd

src/dicomweb_client/__init__.py

@@ -1,4 +1,4 @@
-__version__ = '0.41.1'
+__version__ = '0.41.2'
 
 
 from dicomweb_client.api import DICOMwebClient

src/dicomweb_client/api.py

@@ -403,7 +403,7 @@ def __init__(
             self._session.proxies = proxies
         if callback is not None:
             self._session.hooks = {'response': [callback, ]}
-        if chunk_size is not None:
+        if chunk_size is None:
             # There is a bug in the requests library that sets the Host header
             # again when using chunked transer encoding. Apparently this is
             # tricky to fix (see https://github.com/psf/requests/issues/4392).