data = {
    "user": {
        "profile": {
            "name": "Alice",
            "age": 30
        },
        "settings": {
            "theme": "dark"
        }
    },
    "product": {
        "id": 123
    }
}

# Safely get a nested value that might exist
user_name = data.get("user", {}).get("profile", {}).get("name")
# print(user_name) # Output: Alice

# Safely get a nested value that might not exist, providing a default
non_existent_field = data.get("user", {}).get("preferences", {}).get("language", "en")
# print(non_existent_field) # Output: en

# Without safe access, this would raise KeyError if 'preferences' didn't exist
# user_language_unsafe = data["user"]["preferences"]["language"]
# print(user_language_unsafe) # Raises KeyError