let kallisto =   let url = "https://github.com/pachterlab/kallisto/releases/download/v0.42.3/kallisto_linux-v0.42.3.tar.gz" in   Installable_tool.make Machine.Tool.Default.kallisto ~url     ~witness:(witness_file "kallisto")     ~install_program:KEDSL.Program.(fun ~path ->         shf "cp -r * %s" path       )   ~init_program:add_to_dollar_path