code: def is_gene_list(bed_file):
      
      with utils.open_gzipsafe(bed_file) as in_handle:
          for line in in_handle:
              if not line.startswith("#"):
                  if len(line.split()) == 1:
                      return True
                  else:
                      return False
docs: Check if the file is only a list of genes, not a BED