diff --git a/sample/calculator.py b/sample/calculator.py
index 4da3c60..a82b26d 100644
--- a/sample/calculator.py
+++ b/sample/calculator.py
@@ -9,7 +9,7 @@ def multiply(a, b):
 
 def divide(a, b):
     if b == 0:
-        return "Cannot divide by zero!"
+        raise ValueError("Cannot divide by zero!")
     return a / b
 
 
diff --git a/sample/file_utils.py b/sample/file_utils.py
index 0a17c47..219dd7e 100644
--- a/sample/file_utils.py
+++ b/sample/file_utils.py
@@ -1,11 +1,20 @@
-def read_file(filepath):
-    with open(filepath, "r") as f:
-        data = f.read()
-    return data
+def read_file(filepath: str) -> str:
+    try:
+        with open(filepath, "r") as f:
+            return f.read()
+    except FileNotFoundError:
+        print(f"File not found: {filepath}")
+        return ""
+    except IOError as e:
+        print(f"Error reading file {filepath}: {e}")
+        return ""
 
-def write_file(filepath, content):
-    with open(filepath, "w") as f:
-        f.write(content)
+def write_file(filepath: str, content: str) -> None:
+    try:
+        with open(filepath, "w") as f:
+            f.write(content)
+    except IOError as e:
+        print(f"Error writing to file {filepath}: {e}")
 
 
 # def read_file(filepath: str) -> str:
diff --git a/sample/user.py b/sample/user.py
index b8f101f..5f4bd84 100644
--- a/sample/user.py
+++ b/sample/user.py
@@ -1,23 +1,22 @@
 class User:
-    def __init__(self, username, email):
+    def __init__(self, username: str, email: str):
         self.username = username
         self.email = email
         self.logged_in = False
 
-    def login(self):
+    def login(self) -> None:
         self.logged_in = True
 
-    def logout(self):
+    def logout(self) -> None:
         self.logged_in = False
 
-    def is_logged_in(self):
+    def is_logged_in(self) -> bool:
         return self.logged_in
 
-    def update_email(self, new_email):
+    def update_email(self, new_email: str) -> None:
         if "@" not in new_email:
-            print("Invalid email address!")
-        else:
-            self.email = new_email
+            raise ValueError("Invalid email address")
+        self.email = new_email
 
 
 # class User: