code: def test_l2_prox():
      """Test for l2 prox operator"""
      tensor = T.tensor([2, 4, 4])
      res = l2_prox(tensor, 3)
      true_res = T.tensor([1, 2, 2])
      assert_array_almost_equal(true_res, res)
  
imports: import numpy
  from ...None import backend
  from ..proximal import svd_thresholding, smoothness_prox, soft_thresholding, hals_nnls, fista, active_set_nnls, procrustes, hard_thresholding, soft_sparsity_prox, simplex_prox, normalized_sparsity_prox, monotonicity_prox, unimodality_prox, l2_prox, l2_square_prox, admm
  from ...testing import assert_, assert_array_equal, assert_array_almost_equal
  from tensorly import tensor_to_vec, truncated_svd
  import pytest
label_desc: Use image node_id 8 for calling a global function with example usage: test_l2_prox() without return types