code: def test_constant_sample():
      """Test that a ValueError is raised with a constant sample."""
      discretizer = MultipleCoefficientBinning()
      msg_error = "At least one timestamp is constant."
      with pytest.raises(ValueError, match=msg_error):
          discretizer.fit_transform(np.ones((10, 15)))
  
file_path: pyts/pyts/approximation/tests/test_mcb.py
imports: import numpy
  import pytest
  import re
  from pyts.approximation.mcb import _uniform_bins, _digitize
  from pyts.approximation import MultipleCoefficientBinning
label_desc: Use image node_id 4 for calling a global function with example usage: test_constant_sample() without return types