code: def test_invalid_quantiles():
      """
      Tests generate_equal_height_histogram returns None when quantiles is invalid.
      """
      # Empty quantiles is invalid.
      assert (
          histogram_generator.generate_equal_height_histogram(
              quantiles=[], num_buckets=5
          )
          is None
      )
      # Quantiles which has less than 3 elements is invalid.
      assert (
          histogram_generator.generate_equal_height_histogram(
              quantiles=[1, 2], num_buckets=1
          )
          is None
      )
      # When (len(quantiles) - 1) % num_buckets != 0, quantiles is considered as invalid.
      assert (
          histogram_generator.generate_equal_height_histogram(
              quantiles=[1, 2, 3, 4, 5], num_buckets=3
          )
          is None
      )
  
file_path: mlflow/tests/recipes/cards/test_histogram_generator.py
imports: import pytest
  from google.protobuf import text_format
  from mlflow.protos import facet_feature_statistics_pb2
  from mlflow.recipes.cards import histogram_generator
label_desc: Use image node_id 2 for calling a global function with example usage: test_invalid_quantiles() without return types