Do some refactoring

seleniumbase/plugins/pytest_plugin.py

@@ -1972,7 +1972,10 @@ def pytest_terminal_summary(terminalreporter):
 def _perform_pytest_unconfigure_():
     from seleniumbase.core import proxy_helper
 
-    if not sb_config.multi_proxy:
+    if (
+        (hasattr(sb_config, "multi_proxy") and not sb_config.multi_proxy)
+        or not hasattr(sb_config, "multi_proxy")
+    ):
         proxy_helper.remove_proxy_zip_if_present()
     if hasattr(sb_config, "reuse_session") and sb_config.reuse_session:
         # Close the shared browser session

seleniumbase/plugins/selenium_plugin.py

@@ -1225,7 +1225,10 @@ class SeleniumBrowser(Plugin):
 
     def finalize(self, result):
         """This runs after all tests have completed with nosetests."""
-        if not sb_config.multi_proxy:
+        if (
+            (hasattr(sb_config, "multi_proxy") and not sb_config.multi_proxy)
+            or not hasattr(sb_config, "multi_proxy")
+        ):
             proxy_helper.remove_proxy_zip_if_present()
 
     def afterTest(self, test):