code: def test_min_max_elements(self, col, expected_min_max):
      with test_pipeline.TestPipeline() as p:
          col = p | beam.Create(col)
  
          result = composite_funcs.min_max_elements(
              self.backend, col, "Min and max elements"
          )
  
          beam_util.assert_that(
              result, beam_util.equal_to(expected_min_max)
          )
  
imports: import sys
  import unittest
  from dataclasses import dataclass
  from typing import List
  import apache_beam
  import apache_beam.testing.test_pipeline
  import apache_beam.testing.util
  from absl.testing import parameterized
  import pipeline_dp
  from pipeline_dp import pipeline_functions
  from pipeline_dp import pipeline_backend
label_desc: Use image node_id 6 for calling the BeamBackendTest obj's underlying member method code with example usage: obj.test_min_max_elements(col, expected_min_max) without return types