When writing software, you need tools that make achieving your goal easier and tools that help you to manage the complexity of the code base, which can get millions of line of code and can involve other people's code that you are not experienced with.
Even for small projects, if you are involving third-party libraries, frameworks, and tools, you are, in fact, bringing other people's code into yours and you will need a set of tools to understand what's going on when you rely on this code and to keep your own code under control and free from bugs.
Here is where techniques such as testing, debugging, profiling, and tracing can come in handy to verify the code base, understand what's going on, spot bottlenecks, and see what was executed and when.
The Python standard library comes with many of the tools you will need during daily development to implement...