code: def test_leave_k_out_returns_correct_shape():
      """
      Test that the output matrices are of the same shape as the input matrix.
      """
  
      mat = _get_matrix()
      train, test = leave_k_out_split(mat, K=1)
      assert train.shape == mat.shape
      assert test.shape == mat.shape
  
file_path: implicit/tests/evaluation_test.py
imports: import numpy
  import pytest
  from scipy.sparse import csr_matrix, random
  import implicit
  from implicit.evaluation import leave_k_out_split, precision_at_k, train_test_split
  from implicit.datasets.movielens import get_movielens
label_desc: Use image node_id 4 for calling a global function with example usage: test_leave_k_out_returns_correct_shape() without return types