code: def test_lcss_path_from_metric():
      for be in backends:
          for array_type in array_types:
              for d in np.arange(1, 5):
                  rng = np.random.RandomState(0)
                  s1 = cast(rng.randn(10, d), array_type)
                  s2 = cast(rng.randn(30, d), array_type)
  
                  # Use lcss_path as a reference
                  path_ref, sim_ref = tslearn.metrics.lcss_path(
                      s1, s2, be=be
                  )
  
                  # Test of using a scipy distance function
                  path, sim = tslearn.metrics.lcss_path_from_metric(
                      s1, s2, metric="sqeuclidean", be=be
                  )
  
                  np.testing.assert_equal(path, path_ref)
                  assert isinstance(path, list)
                  np.testing.assert_equal(sim, sim_ref)
                  assert isinstance(sim, float)
  
                  # Test of defining a custom function
                  def sqeuclidean(x, y):
                      return sum((x - y) ** 2)
  
                  path, sim = tslearn.metrics.lcss_path_from_metric(
                      s1, s2, metric=sqeuclidean, be=be
                  )
                  np.testing.assert_equal(path, path_ref)
                  np.testing.assert_equal(sim, sim_ref)
  
                  # Test of precomputing the distance matrix
                  dist_matrix = cdist(s1, s2, metric="sqeuclidean")
                  path, sim = tslearn.metrics.lcss_path_from_metric(
                      dist_matrix, metric="precomputed", be=be
                  )
                  np.testing.assert_equal(path, path_ref)
                  np.testing.assert_equal(sim, sim_ref)
  
imports: import platform
  import sys
  import numpy
  import pytest
  import tslearn.clustering
  import tslearn.metrics
  from scipy.spatial.distance import cdist
  from tslearn.backend.backend import Backend, cast, instantiate_backend
  from tslearn.metrics.dtw_variants import dtw_path
  from tslearn.utils import to_time_series
label_desc: Use image node_id 6 for calling a global function with example usage: test_lcss_path_from_metric() and returns: sum