code: def _close_under_permutations(V, tree_generators):
      vertices = list(range(V))
      trees = []
      for tree in tree_generators:
          trees.extend(
              set(
                  _permute_tree(perm, tree)
                  for perm in itertools.permutations(vertices)
              )
          )
      trees.sort()
      return trees
  
imports: import itertools
  import math
  import torch
  from torch.distributions import constraints
  from torch.distributions.utils import lazy_property
  from pyro.distributions.torch_distribution import TorchDistribution
label_desc: Use image node_id 15 for calling a global function with example usage: _close_under_permutations(V, tree_generators) and returns: trees