Using _ to indicate spaces
class A:
____def f(x):
________a =1
________return a
If you hit delete after the last line, you are taken to column 0 not column 4 because of the empty line. I'm not sure if it's right to completely ignore empty lines - if you un-indent after a function, you don't want to immediately be reindented on the next line? But they definitely should not be considered when finding the "out 1" indentation level.
(This doesn't come up when editing with Reinteract, since it leaves trailing spaces on indented blank lines inside functions ... but does come up when editing existing code.)