code: def _backtransform_ranks(
      arr, c=3 / 8
  ):  # pylint: disable=invalid-name
      """Backtransformation of ranks.
  
      Parameters
      ----------
      arr : np.ndarray
          Ranks array
      c : float
          Fractional offset. Defaults to c = 3/8 as recommended by Blom (1958).
  
      Returns
      -------
      np.ndarray
  
      References
      ----------
      Blom, G. (1958). Statistical Estimates and Transformed Beta-Variables. Wiley; New York.
      """
      arr = np.asarray(arr)
      size = arr.size
      return (arr - c) / (size - 2 * c + 1)
  
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 7 for calling a global function with example usage: _backtransform_ranks(arr, c) and returns: unknown