let mutect2 ?(configuration=Gatk.Configuration.Mutect2.default) bam_pair =     let configuration_name = configuration.Gatk.Configuration.Mutect2.name in     let configuration_json = Gatk.Configuration.Mutect2.to_json configuration in     let make_target         ~run_with ~input ~result_prefix ?more_edges () =       match input with       | Variant_caller.Somatic {normal; tumor} ->         Gatk.mutect2           ~configuration ?more_edges ~run_with           ~input_normal_bam:normal ~input_tumor_bam:tumor           ~result_prefix `Map_reduce in     somatic_variant_caller       {Variant_caller.name = "Mutect";        configuration_json;        configuration_name;        make_target;}       bam_pair