<<rule>> Delete: Multiplicity-Many Containment Reference
<<preserve>>
fromContainedClass : EClass
<<preserve>>
fromContainerClass : EClass
<<delete>>
oldContainmentReference : EReference
<<delete>> unique = "true"
<<delete>> upperBound = value > 1
<<delete>> containment = "true"
<<forbid, pre>>
preContainerReference : EReference
<<delete>>
eType
<<forbid, pre>>
eOpposite
<<forbid, pre>>
eOpposite
<<delete>>
eContainingClass
eStructuralFeatures