code: def ave_qual(quals, qround=False, tab=errs_tab(128)):
      
      if quals:
          mq = -10 * log(sum([tab[q] for q in quals]) / len(quals), 10)
          if qround:
              return round(mq)
          else:
              return mq
      else:
          return None
docs: Calculate average basecall quality of a read.
  
      Receive the integer quality scores of a read and return the average quality for that read
      First convert Phred scores to probabilities,
      calculate average error probability
      convert average back to Phred scale