Format enums-exercise.py with Black and improve code quality

- Format code using Black formatter for consistent style
- Add proper spacing around class definitions
- Break long lines for better readability
- Improve Laptop list formatting with proper indentation
- Add blank line at end of file (Python convention)
- Maintain all functionality while improving code style
- Add comprehensive error handling with try/except blocks
- Use sys.stderr for error messages
- Add sys.exit(1) for proper error termination

Author: Iswanna

prep/enums-exercise.py

@@ -3,11 +3,13 @@
 from enum import Enum
 from typing import List
 
+
 class OperatingSystem(Enum):
     MACOS = "macOS"
     ARCH = "Arch Linux"
     UBUNTU = "Ubuntu"
 
+
 @dataclass(frozen=True)
 class Person:
     name: str
@@ -34,31 +36,62 @@ def find_possible_laptops(laptops: List[Laptop], person: Person) -> List[Laptop]
 
 def create_person_from_input(laptops: List[Laptop]) -> None:
     name = input("Enter person's name: ")
-    age = int(input("Enter person's age: "))
-    
+    try:
+        age = int(input("Enter person's age: "))
+    except ValueError:
+        print("Error: Age must be a number.", file=sys.stderr)
+        sys.exit(1)
+
     print("Available operating systems:")
     for os in OperatingSystem:
         print(f"  {os.name}: {os.value}")
-    
+
     os_choice = input("Enter preferred operating system (MACOS/ARCH/UBUNTU): ").upper()
-    
+
     try:
         preferred_os = OperatingSystem[os_choice]
     except KeyError:
         print("Invalid operating system choice!", file=sys.stderr)
         sys.exit(1)
-    
+
     person = Person(name=name, age=age, preferred_operating_system=preferred_os)
     possible_laptops = find_possible_laptops(laptops, person)
-    
+
     print(f"\nPossible laptops for {person.name}: {possible_laptops}")
-    print(f"The library has {len(possible_laptops)} laptop(s) with {preferred_os.value}")
+    print(
+        f"The library has {len(possible_laptops)} laptop(s) with {preferred_os.value}"
+    )
+
 
 laptops = [
-    Laptop(id=1, manufacturer="Dell", model="XPS", screen_size_in_inches=13, operating_system=OperatingSystem.ARCH),
-    Laptop(id=2, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
-    Laptop(id=3, manufacturer="Dell", model="XPS", screen_size_in_inches=15, operating_system=OperatingSystem.UBUNTU),
-    Laptop(id=4, manufacturer="Apple", model="macBook", screen_size_in_inches=13, operating_system=OperatingSystem.MACOS),
+    Laptop(
+        id=1,
+        manufacturer="Dell",
+        model="XPS",
+        screen_size_in_inches=13,
+        operating_system=OperatingSystem.ARCH,
+    ),
+    Laptop(
+        id=2,
+        manufacturer="Dell",
+        model="XPS",
+        screen_size_in_inches=15,
+        operating_system=OperatingSystem.UBUNTU,
+    ),
+    Laptop(
+        id=3,
+        manufacturer="Dell",
+        model="XPS",
+        screen_size_in_inches=15,
+        operating_system=OperatingSystem.UBUNTU,
+    ),
+    Laptop(
+        id=4,
+        manufacturer="Apple",
+        model="macBook",
+        screen_size_in_inches=13,
+        operating_system=OperatingSystem.MACOS,
+    ),
 ]
 
 people = [
@@ -71,4 +104,4 @@ def create_person_from_input(laptops: List[Laptop]) -> None:
     print(f"Possible laptops for {person.name}: {possible_laptops}")
 
 print("\n--- Create a new person ---")
-create_person_from_input(laptops)
+create_person_from_input(laptops)