code: def _bw_scott(
      x, x_std=None, **kwargs
  ):  # pylint: disable=unused-argument
      """Scott's Rule."""
      if x_std is None:
          x_std = np.std(x)
      bw = 1.06 * x_std * len(x) ** (-0.2)
      return bw
  
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 1 for calling a global function with example usage: _bw_scott(x, x_std) and returns: bw