[py]: Open chromium extension files inside context managers for auto …

…closing

py/selenium/webdriver/chromium/options.py

@@ -18,7 +18,7 @@
 import base64
 import os
 import warnings
-from typing import List, Union
+from typing import List, Union, BinaryIO
 
 from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
 from selenium.webdriver.common.options import ArgOptions
@@ -74,15 +74,17 @@ def extensions(self) -> List[str]:
         """
         :Returns: A list of encoded extensions that will be loaded
         """
-        encoded_extensions = []
-        for ext in self._extension_files:
-            file_ = open(ext, 'rb')
+        def _decode(file_data: BinaryIO) -> str:
             # Should not use base64.encodestring() which inserts newlines every
             # 76 characters (per RFC 1521).  Chromedriver has to remove those
             # unnecessary newlines before decoding, causing performance hit.
-            encoded_extensions.append(base64.b64encode(file_.read()).decode('UTF-8'))
+            return base64.b64encode(file_data.read()).decode("utf-8")
+
+        encoded_extensions = []
+        for extension in self._extension_files:
+            with open(extension, "rb") as f:
+                encoded_extensions.append(_decode(f))
 
-            file_.close()
         return encoded_extensions + self._extensions
 
     def add_extension(self, extension: str) -> None: