Add more detailed docstring

web_view.py

@@ -132,7 +132,27 @@ def index() -> str | Response:
 
 
 def case_flip(s: str) -> str:
-    """Switch case of character."""
+    """
+    Switch the case of a single character.
+
+    If the character is lowercase, it is converted to uppercase. If it is uppercase,
+    it is converted to lowercase. Non-alphabetic characters remain unchanged.
+
+    Args:
+        s (str): A single character string.
+
+    Returns:
+        str: The character with its case flipped, or the original character if it's
+             not a letter.
+
+    Example:
+        >>> case_flip('a')
+        'A'
+        >>> case_flip('A')
+        'a'
+        >>> case_flip('1')
+        '1'
+    """
     if s.islower():
         return s.upper()
     if s.isupper():