There is another Python feature that saves you from this trap however - the nested function. I have lots of code that looks like this: def txform_item(x):

There is another Python feature that saves you from this trap however - the nested function. I have lots of code that looks like this: def txform_item(x): <maybe many lines, as complex as needed, + can see vars in outer scope> # right below, for optimal locality of ref for human reader new_list = [ txform_item(item) for item in old_list ]