Challenge: Optional Arguments

You are working with a simple user management system. Your goal is to implement a function add_user() that adds new users or updates existing ones in a global list called users_db.

The users_db is a list of dictionaries. Each dictionary represents a user and looks like this:

users_db = [
    {"name": "Alice", "age": 28, "role": "admin", "status": "active"}
]

1. Define a function add_user(name, age, role="user", status="active").
2. Check for existing users: Loop through the dictionaries in users_db. Check if the "name" key in any dictionary matches the name argument passed to your function.
3. If the user exists: * Update their existing dictionary with the new age, role, and status.
   • Return the string: "User {name} updated successfully!".
4. If the user doesn’t exist (the loop finishes without finding a match):
   • Create a new dictionary representing the user with the provided name, age, role, and status.
   • Append this new dictionary to users_db.
   • Return the string: "User {name} added successfully!".