code: def get_fastq_files(directory, lane, fc_name):
      
      files = glob.glob(os.path.join(directory, "%s_*%s*txt*" % (lane, fc_name)))
      files.sort()
      if len(files) > 2 or len(files) == 0:
          raise ValueError("Did not find correct files for %s %s %s %s" %
                  (directory, lane, fc_name, files))
      ready_files = []
      for fname in files:
          if fname.endswith(".gz"):
              cl = ["gunzip", fname]
              subprocess.check_call(cl)
              ready_files.append(os.path.splitext(fname)[0])
          else:
              ready_files.append(fname)
      return ready_files[0], (ready_files[1] if len(ready_files) > 1 else None)
docs: Retrieve fastq files for the given lane, ready to process.