[py] Fix mypy errors in by file and exceptions file

py/selenium/webdriver/remote/switch_to.py

@@ -87,7 +87,7 @@ def frame(self, frame_reference: Union[str, int, WebElement]) -> None:
                 try:
                     frame_reference = self._driver.find_element(By.NAME, frame_reference)
                 except NoSuchElementException as exc:
-                    raise NoSuchFrameException(frame_reference) from exc
+                    raise NoSuchFrameException(str(frame_reference)) from exc
 
         self._driver.execute(Command.SWITCH_TO_FRAME, {"id": frame_reference})
 

py/selenium/webdriver/support/relative_locator.py

@@ -18,7 +18,7 @@
 from typing import NoReturn, Optional, Union, overload
 
 from selenium.common.exceptions import WebDriverException
-from selenium.webdriver.common.by import By, ByType
+from selenium.webdriver.common.by import ByType
 from selenium.webdriver.remote.webelement import WebElement
 
 
@@ -48,7 +48,7 @@ def with_tag_name(tag_name: str) -> "RelativeBy":
     warnings.warn("This method is deprecated and may be removed in future versions. Please use `locate_with` instead.")
     if not tag_name:
         raise WebDriverException("tag_name can not be null")
-    return RelativeBy({By.CSS_SELECTOR: tag_name})
+    return RelativeBy({"css selector": tag_name})
 
 
 def locate_with(by: ByType, using: str) -> "RelativeBy":