> A programming language is an abstraction that mostly fully specifies behaviors that any compliant implementation must adhere to, and that you as a user of the

> A programming language is an abstraction that mostly fully specifies behaviors that any compliant implementation must adhere to, and that you as a user of the language can therefore rely on. This is true but hand waves over a lot of behavior. An implementation of Python could be 10x faster or 10x slower and still be fully compliant with the specification. There’s a reason that NumPy’s core is written in C and not Python. The implementation-specific details sometimes matter. The abstraction is leaky as soon as you care about anything not explicitly specified in the abstraction.