code: def _add_coverage_bedgraph_to_output(out, data):
      
      out_file = "%s.coverage.bedgraph" % os.path.splitext(out["cns"])[0]
      if utils.file_exists(out_file):
          out["bedgraph"] = out_file
          return out
      bam_file = dd.get_align_bam(data)
      bedtools = config_utils.get_program("bedtools", data["config"])
      samtools = config_utils.get_program("samtools", data["config"])
      cns_file = out["cns"]
      bed_file = tempfile.NamedTemporaryFile(suffix=".bed", delete=False).name
      with file_transaction(data, out_file) as tx_out_file:
          cmd = ("sed 1d {cns_file} | cut -f1,2,3 > {bed_file}; "
                 "{samtools} view -b -L {bed_file} {bam_file} | "
                 "{bedtools} genomecov -bg -ibam - -g {bed_file} >"
                 "{tx_out_file}").format(**locals())
          do.run(cmd, "CNVkit bedGraph conversion")
          os.remove(bed_file)
      out["bedgraph"] = out_file
      return out
docs: Add BedGraph representation of coverage to the output