file = '/Users/svetlana/Downloads/E.coli.sequence.txt' with open(file, 'r') as fasta:

• starts = {} strtset = set() for line in fasta:

  • if line[0] == '>':

    • nextline = fasta.readline() strtset.add(nextline[0:3]) if nextline[0:3] not in starts:
      • starts[nextline[0:3]] = 1
      else:
      • starts[nextline[0:3]] += 1
  print('Escherichia coli') for codon in sorted(strtset):
  • print(f'{codon} {starts[codon]}')

file = '/Users/svetlana/Downloads/Candidatus_Gracilibacteria_bacterium.txt' with open(file, 'r') as fasta:

• starts = {} strtset = set() for line in fasta:

  • if line[0] == '>':

    • nextline = fasta.readline() strtset.add(nextline[0:3]) if nextline[0:3] not in starts:
      • starts[nextline[0:3]] = 1
      else:
      • starts[nextline[0:3]] += 1
  print('Candidatus Gracilibacteria bacterium') for codon in sorted(strtset):
  • print(f'{codon} {starts[codon]}')

file = '/Users/svetlana/Downloads/Mycoplasma_pneumoniae.sequence.txt' with open(file, 'r') as fasta:

• starts = {} strtset = set() for line in fasta:

  • if line[0] == '>':

    • nextline = fasta.readline() strtset.add(nextline[0:3]) if nextline[0:3] not in starts:
      • starts[nextline[0:3]] = 1
      else:
      • starts[nextline[0:3]] += 1
  print('Mycoplasma pneumoniae') for codon in sorted(strtset):
  • print(f'{codon} {starts[codon]}')