I would turn the question around. Lots of people end up in programming environments, but not all of them are temperamentally suited to be a software engineer. So, say you are interviewing someone and they have 'Python experience'. Ask how long they have been exposed to Python. One day? Then they ought to be able to talk for 10 minutes about the syntax. Six months? They ought to be familiar with the core modules. Someone of any level of experience ought to be interested in the development of the language they are using. People can be exposed to a language for a long time without absorbing the lessons it has to teach.