old_contents: from .standard_deviation import standard_deviation
  from .mean import mean
  
  def coefficient_of_variation(data):
      """
      The `coefficient_of_variation`_ is the ratio of the standard deviation to the mean
      .. _`coefficient of variation`: https://en.wikipedia.org/wiki/Coefficient_of_variation
  
      Args:
          data: A list of numerical objects.
      Returns:
          A float object.
      Examples:
          >>> coefficient_of_variation([1, 2, 3])
          0.5
          >>> coefficient_of_variation([1, 2, 3, 4])
          0.5163977794943222
          >>> coefficient_of_variation([-1, 0, 1, 2, 3, 4])
          1.247219128924647
      """
      return standard_deviation(data) / mean(data)
      
new_contents: from .standard_deviation import standard_deviation
  from .mean import mean
  
  def coefficient_of_variation(data, sample = True):
      """
      The `coefficient of variation`_ is the ratio of the standard deviation to the mean.
  
      .. _`coefficient of variation`: https://en.wikipedia.org/wiki/Coefficient_of_variation
  
      Args:
          data: A list of numerical objects.
      Returns:
          A float object.
      Examples:
          >>> coefficient_of_variation([1, 2, 3])
          0.5
          >>> ss.coefficient_of_variation([1, 2, 3], False)
          0.408248290463863
          >>> coefficient_of_variation([1, 2, 3, 4])
          0.5163977794943222
          >>> coefficient_of_variation([-1, 0, 1, 2, 3, 4])
          1.247219128924647
      """
      return standard_deviation(data, sample) / mean(data)
  
subject: Add sample param to CV function