diff --git a/webdriver_manager/chrome.py b/webdriver_manager/chrome.py
index a8d37f52..c9acf594 100644
--- a/webdriver_manager/chrome.py
+++ b/webdriver_manager/chrome.py
@@ -1,5 +1,6 @@
 import os
 
+from webdriver_manager.core.download_manager import DownloadManager
 from webdriver_manager.core.manager import DriverManager
 from webdriver_manager.core.utils import ChromeType
 from webdriver_manager.drivers.chrome import ChromeDriver
@@ -8,15 +9,15 @@
 class ChromeDriverManager(DriverManager):
     def __init__(
             self,
-            version="latest",
-            os_type=None,
-            path=None,
-            name="chromedriver",
-            url="https://chromedriver.storage.googleapis.com",
-            latest_release_url="https://chromedriver.storage.googleapis.com/LATEST_RELEASE",
-            chrome_type=ChromeType.GOOGLE,
-            cache_valid_range=1,
-            download_manager=None,
+            version: str = "latest",
+            os_type: str = None,
+            path: str = None,
+            name: str = "chromedriver",
+            url: str = "https://chromedriver.storage.googleapis.com",
+            latest_release_url: str = "https://chromedriver.storage.googleapis.com/LATEST_RELEASE",
+            chrome_type: str = ChromeType.GOOGLE,
+            cache_valid_range: int = 1,
+            download_manager: DownloadManager = None,
     ):
         super().__init__(
             path,
@@ -33,7 +34,7 @@ def __init__(
             http_client=self.http_client,
         )
 
-    def install(self):
+    def install(self) -> str:
         driver_path = self._get_driver_path(self.driver)
         os.chmod(driver_path, 0o755)
         return driver_path
diff --git a/webdriver_manager/core/manager.py b/webdriver_manager/core/manager.py
index 9fe2902d..04922ecb 100644
--- a/webdriver_manager/core/manager.py
+++ b/webdriver_manager/core/manager.py
@@ -22,7 +22,7 @@ def __init__(
     def http_client(self):
         return self._download_manager.http_client
 
-    def install(self):
+    def install(self) -> str:
         raise NotImplementedError("Please Implement this method")
 
     def _get_driver_path(self, driver):
diff --git a/webdriver_manager/firefox.py b/webdriver_manager/firefox.py
index 4191722a..ead412d5 100644
--- a/webdriver_manager/firefox.py
+++ b/webdriver_manager/firefox.py
@@ -1,21 +1,22 @@
 import os
 
+from webdriver_manager.core.download_manager import DownloadManager
 from webdriver_manager.core.manager import DriverManager
 from webdriver_manager.drivers.firefox import GeckoDriver
 
 
 class GeckoDriverManager(DriverManager):
     def __init__(
-        self,
-        version="latest",
-        os_type=None,
-        path=None,
-        name="geckodriver",
-        url="https://github.com/mozilla/geckodriver/releases/download",
-        latest_release_url="https://api.github.com/repos/mozilla/geckodriver/releases/latest",
-        mozila_release_tag="https://api.github.com/repos/mozilla/geckodriver/releases/tags/{0}",
-        cache_valid_range=1,
-        download_manager=None,
+            self,
+            version: str = "latest",
+            os_type: str = None,
+            path: str = None,
+            name: str = "geckodriver",
+            url: str = "https://github.com/mozilla/geckodriver/releases/download",
+            latest_release_url: str = "https://api.github.com/repos/mozilla/geckodriver/releases/latest",
+            mozila_release_tag: str = "https://api.github.com/repos/mozilla/geckodriver/releases/tags/{0}",
+            cache_valid_range: int = 1,
+            download_manager: DownloadManager = None,
     ):
         super(GeckoDriverManager, self).__init__(
             path, cache_valid_range, download_manager=download_manager
@@ -31,7 +32,7 @@ def __init__(
             http_client=self.http_client,
         )
 
-    def install(self):
+    def install(self) -> str:
         driver_path = self._get_driver_path(self.driver)
         os.chmod(driver_path, 0o755)
         return driver_path
diff --git a/webdriver_manager/microsoft.py b/webdriver_manager/microsoft.py
index 2e08d788..39d5ded6 100644
--- a/webdriver_manager/microsoft.py
+++ b/webdriver_manager/microsoft.py
@@ -1,6 +1,7 @@
 import os
 
 from webdriver_manager.core import utils
+from webdriver_manager.core.download_manager import DownloadManager
 from webdriver_manager.drivers.edge import EdgeChromiumDriver
 from webdriver_manager.drivers.ie import IEDriver
 from webdriver_manager.core.manager import DriverManager
@@ -8,16 +9,16 @@
 
 class IEDriverManager(DriverManager):
     def __init__(
-        self,
-        version="latest",
-        os_type=None,
-        path=None,
-        name="IEDriverServer",
-        url="https://github.com/seleniumhq/selenium/releases/download",
-        latest_release_url="https://api.github.com/repos/seleniumhq/selenium/releases",
-        ie_release_tag="https://api.github.com/repos/seleniumhq/selenium/releases/tags/selenium-{0}",
-        cache_valid_range=1,
-        download_manager=None,
+            self,
+            version: str = "latest",
+            os_type: str = None,
+            path: str = None,
+            name: str = "IEDriverServer",
+            url: str = "https://github.com/seleniumhq/selenium/releases/download",
+            latest_release_url: str = "https://api.github.com/repos/seleniumhq/selenium/releases",
+            ie_release_tag: str = "https://api.github.com/repos/seleniumhq/selenium/releases/tags/selenium-{0}",
+            cache_valid_range: int = 1,
+            download_manager: DownloadManager = None,
     ):
         super().__init__(path, cache_valid_range, download_manager=download_manager)
         self.driver = IEDriver(
@@ -30,21 +31,21 @@ def __init__(
             http_client=self.http_client,
         )
 
-    def install(self):
+    def install(self) -> str:
         return self._get_driver_path(self.driver)
 
 
 class EdgeChromiumDriverManager(DriverManager):
     def __init__(
-        self,
-        version="latest",
-        os_type=utils.os_type(),
-        path=None,
-        name="edgedriver",
-        url="https://msedgedriver.azureedge.net",
-        latest_release_url="https://msedgedriver.azureedge.net/LATEST_RELEASE",
-        cache_valid_range=1,
-        download_manager=None,
+            self,
+            version: str = "latest",
+            os_type: str = utils.os_type(),
+            path: str = None,
+            name: str = "edgedriver",
+            url: str = "https://msedgedriver.azureedge.net",
+            latest_release_url: str = "https://msedgedriver.azureedge.net/LATEST_RELEASE",
+            cache_valid_range: int = 1,
+            download_manager: DownloadManager = None,
     ):
         super().__init__(path, cache_valid_range, download_manager=download_manager)
         self.driver = EdgeChromiumDriver(
@@ -56,7 +57,7 @@ def __init__(
             http_client=self.http_client,
         )
 
-    def install(self):
+    def install(self) -> str:
         driver_path = self._get_driver_path(self.driver)
         os.chmod(driver_path, 0o755)
         return driver_path
diff --git a/webdriver_manager/opera.py b/webdriver_manager/opera.py
index 22c0cdaf..37c2cc26 100755
--- a/webdriver_manager/opera.py
+++ b/webdriver_manager/opera.py
@@ -1,24 +1,25 @@
 import os
 
+from webdriver_manager.core.download_manager import DownloadManager
 from webdriver_manager.core.manager import DriverManager
 from webdriver_manager.drivers.opera import OperaDriver
 
 
 class OperaDriverManager(DriverManager):
     def __init__(
-        self,
-        version="latest",
-        os_type=None,
-        path=None,
-        name="operadriver",
-        url="https://github.com/operasoftware/operachromiumdriver/"
-        "releases/",
-        latest_release_url="https://api.github.com/repos/"
-        "operasoftware/operachromiumdriver/releases/latest",
-        opera_release_tag="https://api.github.com/repos/"
-        "operasoftware/operachromiumdriver/releases/tags/{0}",
-        cache_valid_range=1,
-        download_manager=None,
+            self,
+            version: str = "latest",
+            os_type: str = None,
+            path: str = None,
+            name: str = "operadriver",
+            url: str = "https://github.com/operasoftware/operachromiumdriver/"
+                       "releases/",
+            latest_release_url: str = "https://api.github.com/repos/"
+                                      "operasoftware/operachromiumdriver/releases/latest",
+            opera_release_tag: str = "https://api.github.com/repos/"
+                                     "operasoftware/operachromiumdriver/releases/tags/{0}",
+            cache_valid_range: int = 1,
+            download_manager: DownloadManager = None,
     ):
         super().__init__(path, cache_valid_range, download_manager=download_manager)
 
@@ -32,7 +33,7 @@ def __init__(
             http_client=self.http_client,
         )
 
-    def install(self):
+    def install(self) -> str:
         driver_path = self._get_driver_path(self.driver)
         if not os.path.isfile(driver_path):
             for name in os.listdir(driver_path):