code: def average_cq(seq, efficiency=1.0):
      
      denominator = sum( [pow(2.0*efficiency, -Ci) for Ci in seq] )
      return log(len(seq)/denominator)/log(2.0*efficiency)
docs: Given a set of Cq values, return the Cq value that represents the
      average expression level of the input.
  
      The intent is to average the expression levels of the samples,
      since the average of Cq values is not biologically meaningful.
  
      :param iterable seq: A sequence (e.g. list, array, or Series) of Cq values.
      :param float efficiency: The fractional efficiency of the PCR reaction; i.e.
          1.0 is 100% efficiency, producing 2 copies per amplicon per cycle.
      :return: Cq value representing average expression level
      :rtype: float