What is a key characteristic of an anonymous function in Python?

An anonymous function in Python is characterized by not having a name. This type of function, typically created using the lambda keyword, allows for the concise definition of simple functions that can be used in a single line of code without requiring a formalized function definition. For instance, a common use of anonymous functions is in scenarios requiring a quick operation for short-term use, such as within the map(), filter(), or sorted() functions.

Unlike named functions defined with the def keyword, anonymous functions are useful for situations where defining a complete function may be cumbersome or unnecessary. They can still take parameters, which contrasts with the notion suggested in one of the options. Additionally, anonymous functions are not limited to being defined within classes; they are freely usable throughout a script or function where they are needed.

In essence, the distinguishing feature of an anonymous function is its lack of a name, allowing developers to streamline their code and improve clarity by minimizing boilerplate.