code: def to_bed(call, sample, work_dir, calls, data):
      
      out_file = os.path.join(work_dir, "%s-%s-flat.bed" % (sample, call["variantcaller"]))
      if call.get("vrn_file") and not utils.file_uptodate(out_file, call["vrn_file"]):
          with file_transaction(data, out_file) as tx_out_file:
              convert_fn = CALLER_TO_BED.get(call["variantcaller"])
              if convert_fn:
                  vrn_file = call["vrn_file"]
                  if call["variantcaller"] in SUBSET_BY_SUPPORT:
                      ecalls = [x for x in calls if x["variantcaller"] in SUBSET_BY_SUPPORT[call["variantcaller"]]]
                      if len(ecalls) > 0:
                          vrn_file = _subset_by_support(call["vrn_file"], ecalls, data)
                  convert_fn(vrn_file, call["variantcaller"], tx_out_file)
      if utils.file_exists(out_file):
          return out_file
docs: Create a simplified BED file from caller specific input.