Python is based on mainly on statements rather than expressions, and lambdas can’t have multiple statements, so writing lambdas is different from writing normal Python code.

In a very real sense, there is no idiomatic way to write complex lambdas in Python. What you would do instead is define a named function and pass it in as an argument. This is fine but definitely more complicated.

- No multi-line support

- Gets very messy when nested

And SICP is a book about learning computer science by abusing lambdas.