docs: def set_observable(self,tseq,qseq):
      """Set the observable sequence data
  
      :param tseq: target sequence (from the homopolymer)
      :param qseq: query sequence ( from the homopolymer)
      :type tseq: string
      :type qseq: string
  
      """
      tnt = None
      qnt = None
      if len(tseq) > 0: tnt = tseq[0]
      if len(qseq) > 0: qnt = qseq[0]
      self._observable.set(len(tseq),len(qseq),tnt,qnt)