No, it's something opposite from good practice. Typically you'll call something in the other language from Python script if that language is much quicker (usually C) or provides libraries for some complex analysis that'll be untrivial to reproduce in python (in my experience R, but that depends on the domain).
PHP doesn't give you either advantage, so it's better to redo everything in Python. Your code will be easier to maintain, requiring no PHP knowledge; it'll have better architecture; you won't have a PHP (and probably some libraries thereof) as a dependency; and, most likely, it'll be quicker.