code: def standarddev(x, avgx=None, bessel=False):
      """
      Args:
        x: iterable with len
  
        bessel: (default ``False``) to be passed to the average to divide by
        ``N - 1`` (Bessel's correction)
  
      Returns:
        A float with the standard deviation of the elements of x
      """
      return math.sqrt(average(variance(x, avgx), bessel=bessel))
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import math
label_desc: Use image node_id 3 for calling a global function with example usage: standarddev(x, avgx, bessel) and returns: math