How to add a custom xmlns to bpmn2:definitions element

Users
1

Hi all! I have a problem, when I create a new bpmn diagram by bpmnModeler.createDiagram, I want to add a custom xmlns ‘xmlns:teaflow’ to bpmn2:definitions element, but it failed. What should I do?
My js code is below:
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What I got is below:
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The results I expect is below:
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2

Is this namespace being used anywhere in the diagram? If not, it will be removed on export.

3

Thank you very much, it is really as you say!!