code: def fq_merge(R1, R2):
      
      c = itertools.cycle([1, 2, 3, 4])
      for r1, r2 in zip(R1, R2):
          n = next(c)
          if n == 1:
              pair = [[], []]
          pair[0].append(r1.strip())
          pair[1].append(r2.strip())
          if n == 4:
              yield pair
docs: merge separate fastq files