code: def _aad(X):
      """Internal Function to Calculate Average Absolute Deviation
      (a.k.a Mean Absolute Deviation)
      """
      return np.mean(np.absolute(X - np.mean(X)))
  
file_path: pyod/pyod/models/lmdd.py
imports: from __future__ import division
  from __future__ import print_function
  import numpy
  from numba import njit
  from scipy import stats
  from sklearn.utils import check_array, check_random_state
  from pyod.utils import check_parameter
  from .base import BaseDetector
label_desc: Use image node_id 1 for calling a global function with example usage: _aad(X) and returns: np