code: def multivariate_mean_shift():
      """Generate simple mean shift time series."""
      x = np.concatenate(tuple(np.ones(5) * i**2 for i in range(4)))
      return np.vstack((x, x.max() - x)).T
  
file_path: sktime/sktime/annotation/tests/test_igts.py
imports: import numpy
  import pytest
  from sktime.annotation.igts import IGTS, InformationGainSegmentation, entropy
label_desc: Use image node_id 1 for calling a global function with example usage: multivariate_mean_shift() and returns: np