code: def _mature(subseq, absolute, c,  size=33, total=5000):
      
      reads = dict()
      probs = [0.1, 0.2, 0.4, 0.2, 0.1]
      end = 5 + size
      error = [-2, -1, 0, 1, 2]
      for error5 in error:
          for error3 in error:
              s = 5 - error5
              e = end - error3
              seen = subseq[s:e]
              counts = int(probs[error5 + 2] * probs[error3 + 2] * total) + 1
              name = "seq_%s_%s_%s_x%s" % (c, s + absolute, e + absolute, counts)
              reads[name] = (seen, counts)
      return reads
docs: Create mature sequences around start/end