code: def _is_multilabel(y: np.ndarray) -> bool:
      """Checks whether `y` is in a multi-label indicator matrix format.
  
      Sparse matrices are not supported.
      """
      if not (
          isinstance(y, np.ndarray) and y.ndim == 2 and y.shape[1] > 1
      ):
          return False
      return np.array_equal(np.unique(y), [0, 1])
  
file_path: cleanlab/cleanlab/internal/multilabel_utils.py
imports: from typing import Tuple, Optional, List
  import numpy
  from cleanlab.internal.util import get_num_classes
label_desc: Use image node_id 1 for calling a global function with example usage: _is_multilabel(y) and returns: np, False