code: def _get_contrast_indices(effect_idx, n_factors):  # noqa: D401
      """Henson's factor coding, see num2binvec."""
      binrepr = np.binary_repr(effect_idx, n_factors)
      return np.array([int(i) for i in binrepr], dtype=int)
  
file_path: mne-python/mne/stats/parametric.py
imports: from functools import reduce
  from string import ascii_uppercase
  import numpy
  from scipy import stats
  from scipy.signal import detrend
  from ..utils import _check_option
label_desc: Use image node_id 5 for calling a global function with example usage: _get_contrast_indices(effect_idx, n_factors) and returns: np