I read lots of people complaining about medium-to-large scale Python projects, due to lack of static typing. Aren't people using reflection and dynamic in C#? A

I read lots of people complaining about medium-to-large scale Python projects, due to lack of static typing. Aren't people using reflection and dynamic in C#? As soon as the code touches such run-time features, the testing at run-time is essential. I wonder how large projects such as OpenStack, Django, Edx, PyPy deal without static types?