I installed ArcREST as specified via command prompt successfully using python setup.py install command from the directory. When running the tool Delete Data from Feature Service, either using the script tool or python IDLE, the tool fails.
ImportError: No module named six
Hello Ernesto,
Seems like this was an issue that got fixed: https://github.com/Esri/ArcREST/issues/163
You might want to try downloading and installing again.