code: def coefficient_of_variation(data, data_mean=None, data_stdev=None):
      
      data_mean = data_mean or mean(data)
      data_stdev = data_stdev or stdevp(data, data_mean)
      if data_mean == 0:
          return float("inf") if data_stdev != 0 else 0
      else:
          return data_stdev / data_mean
docs: Return the coefficient of variation (CV) of a sequence of numbers.
      :param data_mean: Precomputed mean of the sequence.
      :param data_stdevp: Precomputed stdevp of the
          sequence.