[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-1)from functools import singledispatch
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-2)
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-3)@singledispatch 
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-4)def greet(x): return "Hello stranger!"
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-5)
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-6)@greet.register
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-7)def _(x:str): return f"Hello {x}!"
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-8)
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-9)@greet.register
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-10)def _(x:int): return f"Hello number {x}!"
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-11)
[](https://www.fast.ai/posts/2025-02-20-fasttransform.html#cb24-12)greet(None), greet("Alice"), greet(42)