code: def test_R2_score():
      """Test for RMSE"""
      X_original = tl.randn((5, 4, 3))
      assert R2_score(X_original, X_original) == 1.0
      assert R2_score(X_original, X_original * 2) == 0.0
      assert R2_score(X_original, tl.zeros_like(X_original)) == 0.0
  
imports: import numpy
  import tensorly
  from ..regression import MSE, RMSE, R2_score, correlation
  from ...testing import assert_array_almost_equal
label_desc: Use image node_id 3 for calling a global function with example usage: test_R2_score() without return types