Open source libraries have high quality standards. And understandably so, since the more important and widely used a project becomes, the more essential it is to maintain it. But this at times affects one of the fundamental advantages of open source software - contributions. Strict quality requirements and harsh code reviews make the process of contributing patches discouraging, disappointing, and even stressful. In this talk, I will discuss tools and processes used by major Python libraries to maintain a high level of code quality and a robust code review culture. I will work through a list of people's code review fears with personal anecdotes, and how to deal with them and be more receptive to critical feedback. Through real examples taken from popular open source Python libraries, I will try to show what makes a good code review, what makes a bad code review, and what minor changes can turn the latter into the former.