[py] update driver constructor typing

py/selenium/webdriver/chromium/webdriver.py

diff --git a/py/selenium/webdriver/chromium/webdriver.py b/py/selenium/webdriver/chromium/webdriver.py
index 6bd61f7..3d9b94a 100644
--- a/py/selenium/webdriver/chromium/webdriver.py
+++ b/py/selenium/webdriver/chromium/webdriver.py
@@ -28,11 +28,11 @@
 
     def __init__(
         self,
-        browser_name,
-        vendor_prefix,
-        options: ArgOptions,
-        service: Service,
-        keep_alive=True,
+        browser_name: str = None,
+        vendor_prefix: str = None,
+        options: ArgOptions = ArgOptions(),
+        service: Service = None,
+        keep_alive: bool = True,
     ) -> None:
         """Creates a new WebDriver instance of the ChromiumDriver. Starts the
         service and then creates new WebDriver instance of ChromiumDriver.

py/selenium/webdriver/firefox/webdriver.py

diff --git a/py/selenium/webdriver/firefox/webdriver.py b/py/selenium/webdriver/firefox/webdriver.py
index b7ae38a..574f2ee 100644
--- a/py/selenium/webdriver/firefox/webdriver.py
+++ b/py/selenium/webdriver/firefox/webdriver.py
@@ -42,7 +42,7 @@
         self,
         options: Options = None,
         service: Service = None,
-        keep_alive=True,
+        keep_alive: bool = True,
     ) -> None:
         """Creates a new instance of the Firefox driver. Starts the service and
         then creates new instance of Firefox driver.

py/selenium/webdriver/ie/webdriver.py

diff --git a/py/selenium/webdriver/ie/webdriver.py b/py/selenium/webdriver/ie/webdriver.py
index aba6940..3c9872b 100644
--- a/py/selenium/webdriver/ie/webdriver.py
+++ b/py/selenium/webdriver/ie/webdriver.py
@@ -31,7 +31,7 @@
         self,
         options: Options = None,
         service: Service = None,
-        keep_alive=True,
+        keep_alive: bool = True,
     ) -> None:
         """Creates a new instance of the Ie driver.
 
@@ -40,7 +40,7 @@
         :Args:
          - options - IE Options instance, providing additional IE options
          - service - (Optional) service instance for managing the starting and stopping of the driver.
-         - keep_alive - Deprecated: Whether to configure RemoteConnection to use HTTP keep-alive.
+         - keep_alive - Whether to configure RemoteConnection to use HTTP keep-alive.
         """
 
         self.service = service if service else Service()