docs: def _outer_to_numpy_indexer(key, shape):
      """Convert an OuterIndexer into an indexer for NumPy.
  
      Parameters
      ----------
      key : Basic/OuterIndexer
          An indexer to convert.
      shape : tuple
          Shape of the array subject to the indexing.
  
      Returns
      -------
      tuple
          Tuple suitable for use to index a NumPy array.
      """
      if len([k for k in key.tuple if not isinstance(k, slice)]) <= 1:
          # If there is only one vector and all others are slice,
          # it can be safely used in mixed basic/advanced indexing.
          # Boolean index should already be converted to integer array.
          return key.tuple
      else:
          return _outer_to_vectorized_indexer(key, shape).tuple