Working with files in Python is pretty easy. But there’s a common mistake that can sneak into your code. Not closing the file ...

Black reformats Python code into a singular, consistent, and readable style, drawing on internal rules for handling tricky problems like multiline expressions, so even those get reformatted ...

Although Python code is almost always fast enough for the task, sometimes it isn’t. In those cases, you need to find out where and why it lags, and do something about it.