code: def append(self, v):
      raise ValueError("%s may not be modified" % type(self).__name__)
  
imports: from nltk.probability import ProbabilisticMixIn
  from nltk.tree.parented import MultiParentedTree, ParentedTree
  from nltk.tree.tree import Tree
label_desc: Use image node_id 8 for calling the ImmutableTree obj's underlying member method code with example usage: obj.append(v) without return types