let bam_left_align ~reference_build bamf =     let bam = get_bam (AF.get_file bamf) in     let output =       Name_file.from_path bam#product#path ~readable_suffix:"_left-aligned.bam"         [Filename.basename bam#product#path] in     Bam (Tools.Freebayes.bam_left_align ~reference_build ~bam ~run_with output)     |> AF.with_provenance "bam-left-align" ["bam", AF.get_provenance bamf]       ~string_arguments:["reference-build", reference_build]