code: def test_format_multiannotator_labels():
      str_labels = np.array(
          [
              ["a", "b", "c"],
              ["b", "b", np.NaN],
              ["z", np.NaN, "c"],
          ]
      )
      labels, label_map = format_multiannotator_labels(str_labels)
  
      assert isinstance(labels, pd.DataFrame)
      assert label_map[0] == "a"
      assert label_map[3] == "z"
  
      num_labels = pd.DataFrame(
          [
              [3, 2, 1],
              [1, 2, np.NaN],
              [3, np.NaN, 3],
          ]
      )
      labels, label_map = format_multiannotator_labels(num_labels)
  
imports: import numpy
  import pytest
  from copy import deepcopy
  from cleanlab.benchmarking.noise_generation import generate_noise_matrix_from_trace
  from cleanlab.benchmarking.noise_generation import generate_noisy_labels
  from cleanlab import count
  from cleanlab.multiannotator import get_label_quality_multiannotator, get_label_quality_multiannotator_ensemble, get_active_learning_scores, get_active_learning_scores_ensemble, get_majority_vote_label, convert_long_to_wide_dataset
  from cleanlab.internal.multiannotator_utils import format_multiannotator_labels
  import pandas
  from sklearn.linear_model import LogisticRegression
label_desc: Use image node_id 15 for calling a global function with example usage: test_format_multiannotator_labels() without return types