new_contents: from . import Operation
  
  class SetTransformOperation(Operation.Operation):
      def __init__(self, node, transform):
          super().__init__()
          self._node = node
          self._old_transform = node.getLocalTransformation()
          self._new_transform = transform
  
      def undo(self):
          self._node.setLocalTransformation(self._old_transform)
  
      def redo(self):
          self._node.setLocalTransformation(self._new_transform)
  
      def mergeWith(self, other):
          if type(other) is not SetTransformOperation:
              return False
  
          if other._node != self._node:
              return False
  
          op = SetTransformOperation(self._node, self._new_transform)
          op._old_transform = other._old_transform
          return op
  
      def __repr__(self):
          return "SetTransformOperation(node = {0}, old_transform={1}, new_transform={2})".format(self._node, self._old_transform, self._new_transform)
  
subject: Add a SetTransformOperation class to explicitly set a transformation matrix