E ImportError: cannot import name EntityAdaptercubicweb_varnish/entities.py:19: ImportError=========================== 1 failed in 1.02 seconds ===========================ERROR: InvocationError for command /builds/cubicweb/cubes/varnish/.tox/py27/bin/python -m pytest test (exited with code 1)___________________________________ summary ____________________________________ERROR: py27: commands failedCleaning up file based variablesERROR: Job failed: command terminated with exit code 1