code: def _sturges_formula(dataset, mult=1):
      """Use Sturges' formula to determine number of bins.
  
      See https://en.wikipedia.org/wiki/Histogram#Sturges'_formula
      or https://doi.org/10.1080%2F01621459.1926.10502161
  
      Parameters
      ----------
      dataset: xarray.DataSet
         Must have the `draw` dimension
  
      mult: float
          Used to scale the number of bins up or down. Default is 1 for Sturges' formula.
  
      Returns
      -------
      int
          Number of bins to use
      """
      return int(np.ceil(mult * np.log2(dataset.draw.size)) + 1)
  
imports: import warnings
  import numpy
  from scipy.fftpack import fft
  from scipy.optimize import brentq
  from scipy.signal import convolve, convolve2d, gaussian
  from scipy.sparse import coo_matrix
  from scipy.special import ive
  from ..utils import _cov, _dot, _stack, conditional_jit
label_desc: Use image node_id 22 for calling a global function with example usage: _sturges_formula(dataset, mult) and returns: int