Message10565

First, please submit your bug with some more explanatory text so we don't have to dig through a zip file to triage.

Related bug is #1878

I see you also tried this on Jython 2.7, so there's some additional diagnostic output to consider:

TypeError: Supertypes that share a modified attribute have an MRO conflict[
attribute=remove,
supertypes=[
<type 'org.eclipse.emf.ecore.util.DelegatingNotifyingInternalEListImpl'>,
<type 'java.util.AbstractList'>,
<type 'org.eclipse.emf.common.util.DelegatingEList'>,
<type 'org.eclipse.emf.common.util.AbstractEList'>,
<type 'org.eclipse.emf.common.notify.NotifyingList'>,
<type 'org.eclipse.emf.common.notify.impl.DelegatingNotifyingListImpl'>,
<type 'org.eclipse.emf.common.util.EList'>,
<type 'java.util.List'>,
<type 'org.eclipse.emf.ecore.util.InternalEList'>
],
type=DelegatingFeatureMap]

It looks like the same problem we saw in #1878 - DelegatingFeatureMap is a Map that implements Iterable