All languages, including python, where you do a lot of asynchronous io require callbacks all the time. It's only recently python got await-support to deal with

All languages, including python, where you do a lot of asynchronous io require callbacks all the time. It's only recently python got await-support to deal with this. Single line lambdas is a real PITA when your not using asyncio and python maintainers have said they don't plan to change it :(