Import error: cannot import name EventConstants

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Mac OS X : 10.12.6
PsychoPy version : 1.90
**Standard Standalone? ** : yes

Hello,
I am trying to insert a code snippet into my experiment to rotate gratings using iohub, but before I can get anything to run the program stops with an error message:

from psychopy.iohub import launchHubServer, EventConstants
ImportError: cannot import name EventConstants

Any help would be appreciated! Thank you.

Try this:

from psychopy.iohub.constants import EventConstants