let varscan_somatic ?adjust_mapq bam_pair =
    let configuration_name =
      sprintf "amq-%s"
        (Option.value_map ~default:"NONE" adjust_mapq ~f:Int.to_string) in
    let configuration_json =
      `Assoc [
        "Name", `String configuration_name;
        "Adjust_mapq",
        `String (Option.value_map adjust_mapq ~f:Int.to_string ~default:"None");
      ] in
    somatic_variant_caller
      {Variant_caller.name = "Varscan-somatic";
       configuration_json;
       configuration_name;
       make_target = begin
         fun ~run_with ~input ~result_prefix ?more_edges () ->
           match input with | Variant_caller.Somatic {normal; tumor} ->
           Varscan.somatic_map_reduce ?adjust_mapq
             ?more_edges ~run_with ~normal ~tumor ~result_prefix ()
       end}
      bam_pair