code: def _z_fold(ary):
      """Fold and z-scale values."""
      ary = np.asarray(ary)
      ary = abs(ary - np.median(ary))
      ary = _z_scale(ary)
      return ary
  
imports: import warnings
  from collections.abc import Sequence
  import numpy
  import packaging
  import pandas
  import scipy
  from scipy import stats
  from ..data import convert_to_dataset
  from ..utils import Numba, _numba_var, _stack, _var_names
  from .density_utils import histogram
  from .stats_utils import _circular_standard_deviation, _sqrt
  from .stats_utils import autocov
  from .stats_utils import not_valid
  from .stats_utils import quantile
  from .stats_utils import stats_variance_2d
  from .stats_utils import wrap_xarray_ufunc
label_desc: Use image node_id 10 for calling a global function with example usage: _z_fold(ary) and returns: ary