The current httpx doesn't support proxies arguments:

https://github.com/encode/httpx/blob/master/httpx/_client.py#L239

Author: brokenjade3000

scholarly/_proxy_generator.py

@@ -483,6 +483,10 @@ def _new_session(self, **kwargs):
                 # ScraperAPI requests to work.
                 # https://www.scraperapi.com/documentation/
                 init_kwargs["verify"] = False
+            if 'proxies' in init_kwargs:
+                proxy=init_kwargs['proxies']['https://']
+                del init_kwargs['proxies']
+                init_kwargs['proxy'] = proxy                       
         self._session = httpx.Client(**init_kwargs)
         self._webdriver = None