code: def fq2fa(fq):
      
      c = cycle([1, 2, 3, 4])
      for line in fq:
          n = next(c)
          if n == 1:
              seq = ['>%s' % (line.strip().split('@', 1)[1])]
          if n == 2:
              seq.append(line.strip())
              yield seq
docs: convert fq to fa