code: def get_depth_per_transcript(self,mindepth=1):
      
      bedarray = []
      for tx in self.get_transcripts():
        for ex in [x.range for x in tx.exons]: bedarray.append(ex)
      cov = ranges_to_coverage(bedarray)
      results = {}
      for tx in self.get_transcripts():
        tlen = tx.length #mapped length
        bcov = []
        for ex in [x.range for x in tx.exons]:     
          excov = [[x.overlap_size(ex),x.payload] for x in cov]
          for coved in [x for x in excov if x[0] > 0]:
            bcov.append(coved)
        total_base_coverage = sum([x[0]*x[1] for x in bcov])
        average_coverage = float(total_base_coverage)/float(tlen)
        minimum_bases_covered = sum([x[0] for x in bcov if x[1] >= mindepth])
        fraction_covered_at_minimum = float(minimum_bases_covered)/float(tlen)
        res = {'tx':tx,'average_coverage':average_coverage,'fraction_covered':fraction_covered_at_minimum,'mindepth':mindepth,'length_covered':minimum_bases_covered}
        results[tx.id] = res
        #print average_coverage
        #print fraction_covered_at_minimum
        #print tlen
        #tcov = float(bcov)/float(tlen)
        #print tcov
      #for c in cov:
      #  print c
      return results
docs: using all the transcripts find the depth