Raising Exceptions (The raise keyword)

Sometimes, you want to trigger an error manually when a specific condition is violated in your program (e.g., a user enters a negative value for age). We do this using the raise keyword.

def check_age(age):
    if age < 0:
        # Manually throw an error
        raise ValueError("Age cannot be negative!")
    print(f"Age {age} is valid.")

try:
    check_age(-5)
except ValueError as e:
    print("Caught manual error:", e)
# Output: Caught manual error: Age cannot be negative!

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