please upgrade pip with latest version..
currently there is version with from core import ... in __init__.py
You can try
pip install git+https://github.com/locustio/locust.git
as a workaround.
A new pre-prelease version was released last week. You need to specify the version explicitly (since it's marked as alpha):
pip install locustio==0.8a2
Most helpful comment
A new pre-prelease version was released last week. You need to specify the version explicitly (since it's marked as alpha):