Wrong string type.

smwrappers/explore_mapping_parameters/wrapper.py

@@ -67,7 +67,7 @@ with NamedTemporaryFile() as fastq, NamedTemporaryFile() as rates_record:
     (best_rate, best_settings) = max(
         (float(rate), settings)
         for (rate, settings)
-        in map(str.split, rates_record))
+        in map(bytes.split, rates_record))
     with open(snakemake.output.mapping_params, "w") as fh:
         fh.write(f"{best_params}\t({best_rate}%%)\n")