code: def model_length(gene, domain):
      
      if gene == '16S':
          domain2max = {'E_coli_K12': int(1538), 'bacteria': int(1689), 'archaea': int(1563), 'eukarya': int(2652)}
          return domain2max[domain]
      elif gene == '23S':
          domain2max = {'E_coli_K12': int(2903), 'bacteria': int(3146), 'archaea': int(3774), 'eukarya': int(9079)}
          return domain2max[domain]
      else:
          print(sys.stderr, '# length unknown for gene: %s, domain: %s' % (gene, domain))
          exit()
docs: get length of model