Template query - show how to edit a constraint

https://github.com/intermine/intermine-ws-python-docs/blob/master/07-tutorial.ipynb
The tutorial mentions editing the constraint, but doesn't show you how to do it.

Open 07-tutorial.ipynb and find the template query section that mentions editing a constraint. Add a worked example showing how to edit the constraint, then run through the tutorial to confirm the example is understandable and works as described.

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