There is a parent , that has got only one child .
And that child has got many childrens.
The return type of getModelChildren() is List. But the return type in the
model is the object of the child itself i.e. getTree() which returns Tree,
not EList Type.
What i have done in create command i have created an object of
EObjectContainmentList() and provided the values, but this also doesnt
works.