Update comments

Author: mdmintz

examples/test_contains_selector.py

@@ -1,3 +1,6 @@
+""" TAG:contains("TEXT") is a special, non-standard CSS Selector
+    that gets converted to XPath: '//TAG[contains(., "TEXT")]'
+    before it's used by Selenium calls. Also part of jQuery. """
 from seleniumbase import BaseCase
 
 

examples/test_mfa_login.py

@@ -6,8 +6,11 @@ def test_mfa_login(self):
         self.open("https://seleniumbase.io/realworld/login")
         self.type("#username", "demo_user")
         self.type("#password", "secret_pass")
-        self.enter_mfa_code("#totpcode", "GAXG2MTEOR3DMMDG")
-        self.highlight("img#image1")
+        self.enter_mfa_code("#totpcode", "GAXG2MTEOR3DMMDG")  # 6-digit
+        self.highlight("img#image1")  # A fancier assert_element() call
         self.click('a:contains("This Page")')
         self.assert_text("Welcome!", "h1")
-        self.save_screenshot_to_logs()
+        self.save_screenshot_to_logs()  # In "./latest_logs/" folder.
+        self.click_link("Sign out")  # Must be "a" tag. Not "button".
+        self.assert_element('a:contains("Sign in")')
+        self.assert_text("You have been signed out!", "#top_message")