How to set the number of drones?

[zhaoxuesi]

I am so sorry that I do not find how to set the number of drones. With the default setting, there are two drones and the rendering time is very fast (learning.py). However, the picture in readme.md shows 6 drones, which confuses me.

[JacopoPan]

All classes extending BaseAviary.py expose argument num_drones, you will find it being set in most of the scripts in the examples/ folder