What would be the outcome of trying to access an undefined attribute in a class?

Accessing an undefined attribute in a class will lead to Python raising an AttributeError. This is because Python's object-oriented programming model expects class attributes to be explicitly defined. When you attempt to access an attribute that hasn't been defined in the class, Python checks the class itself and its parent classes for the attribute and, failing to find it, raises an error.

This behavior is essential as it helps programmers identify potential issues in their code. By raising an AttributeError, Python informs the developer that they are trying to use a property that does not exist, preventing the program from continuing to run under false assumptions. This feature is part of Python's dynamic nature in which attributes can be added or modified at runtime, yet it still enforces a level of consistency and validation by alerting the user when an undefined attribute is accessed.