Some network teams are finding power and simplicity in the shift from telling devices what to do—imperative programming—to describing what they should be—declarative programming.

Despite a rocky transition from Python 2 to Python 3, developers are still flocking to the programming language.

“I CERTAINLY didn’t set out to create a language that was intended for mass consumption,” says Guido van Rossum, a Dutch computer scientist who devised Python, a programming language, in ...