code: def check_read_lengths(ribo_file, read_lengths):
      
      # check if there are any valid read lengths to check i.e., not equal to 0
      valid_lengths = list(set(read_lengths))
      # if read length is 0, all read lengths are requested so we skip further
      # checks.
      if len(valid_lengths) == 1 and valid_lengths[0] == 0:
          return
      for read_length in valid_lengths:
          if read_length < 0:
              msg = 'Read length must be a positive value'
              log.error(msg)
              raise ArgumentError(msg)
docs: Check if read lengths are valid (positive).