how can I recognize multiple faces from one image in python
In general, you perform object detection to find potential faces, and then you perform face recognition on the face(s) detected.

This article walks through the various steps quite well:
https://medium.com/@ageitgey/machine-learning-is-fun-part-4-modern-face-recognition-with-deep-learning-c3cffc121d78

The author also has a Python library that does recognition of multiple faces in a scene with video examples:
https://github.com/ageitgey/face_recognition