docs: def has_ndarray_int_columns(features, X):
      """ Checks if numeric feature columns exist in ndarray """
      _, ncols = X.shape
      if not all(d.isdigit() for d in features if isinstance(d, str)) or not isinstance(X, np.ndarray):
          return False
      ndarray_columns = np.arange(0, ncols)
      feature_cols = np.unique([int(d) for d in features])
      return all(np.in1d(feature_cols, ndarray_columns))