PythonLiveLessons #1: Completing a code sketch

This is the second episode of #PythonLiveLessons, a weekly live stream about Python code and more, hosted by Sebastiaan Mathôt. In this episode, we'll pick up were we left off last week, when we started a new Python project, `markdown_code_exec`, from scratch. We'll learn about the difference between expressions and statements, and the difference between eval() and exec(). At the end of this episode, we'll have a fully functional 'sketch' of our program, which we'll develop further in future episodes!