code: def fit_transform(self, tensor):
      self.decomposition_ = tensor_train_OI(
          tensor,
          rank=self.rank,
          n_iter=self.n_iter,
          trajectory=self.trajectory,
          return_errors=self.return_errors,
      )
      return self.decomposition_
  
file_path: tensorly/tensorly/contrib/decomposition/tt_TTOI.py
imports: import numpy
  import tensorly
  from tensorly.tt_tensor import tt_to_tensor, validate_tt_rank
  from tensorly.decomposition._base_decomposition import DecompositionMixin
label_desc: Use image node_id 2 for calling the TensorTrain_OI obj's underlying member method code with example usage: obj.fit_transform(tensor) and returns: self