Even Python 3 makes it easy to ignore how things work. open happily accepts a string. Regex works on bytes. open and the standard streams can be used for reading and writing without explicitly specifying any encoding or error handling strategy. There's a default value for encoding on codec.encode and codec.decode. And nothing is checked statically, so you get to discover all your mistakes at runtime—and often only with a specific combination of inputs and environment.

People don't think about these things because Python encourages you to ignore them. Until it doesn't. There'd be a lot less confusion if Python 3 were more strict/explicit about conversions.