How to use the dxpy.DXGTable function in dxpy

filename += '.csv' if args.csv else '.tsv'
        if not args.overwrite and os.path.exists(filename):
            parser.exit(1, fill('Error: path \"' + filename + '\" already exists but -f/--overwrite was not set') + '\n')
        writer = csv.writer(open(filename, 'wb'),
                            delimiter=delimiter)
    if not args.no_header:
        writer.writerow((['__id__:int'] if args.rowid else []) + [(col['name'] + ':' + col['type']) for col in dxtable.describe()['columns']])

    # Query stuff
    if args.gri is not None:
        try:
            lo = int(args.gri[1])
            hi = int(args.gri[2])
        except:
            parser.exit(1, fill('Error: the LO and HI arguments to --gri must be integers') + '\n')
        gri_query = dxpy.DXGTable.genomic_range_query(args.gri[0],
                                                      lo,
                                                      hi,
                                                      args.gri_mode,
                                                      args.gri_name)
        iterator = dxtable.iterate_query_rows(query=gri_query, limit=args.limit)
    else:
        iterator = dxtable.iterate_rows(start=args.starting, end=(None if args.limit is None else args.starting + args.limit))
    for row in iterator:
        writer.writerow([str(item).encode('utf-8') for item in row[0 if args.rowid else 1:]])

if opts.genes_id == None:
        parser.print_help()
        sys.exit(1)
        
    if opts.file_name != None:
        outputFile = open(opts.file_name, 'w')
    else:
        outputFile = None
        

    if opts.genes_id == None:
        parser.print_help()
        sys.exit(1)

    tableId = opts.genes_id
    table = dxpy.DXGTable(tableId)
    
    genesTypes = {"exon": True, "CDS":True, "5' UTR": True, "3' UTR": True, "transcript":True, "gene":True}
    translatedTypes = {"transcript":"mRNA", "5' UTR": "five_prime_UTR", "3' UTR":"three_prime_UTR"}
    
    columns = table.get_col_names()
    idColumn = None
    parentColumn = None
    if "ID" in columns:
        idColumn = "ID"
    elif "Id" in columns:
        idColumn = "Id"
    elif "id" in columns:
        idColumn = "id"
    else:
        idColumn = "span_id"

def main(**kwargs):
    if len(kwargs) == 0:
        kwargs = vars(arg_parser.parse_args(sys.argv[1:]))

    if "end_row" not in kwargs:
        kwargs["end_row"] = None

    if kwargs["end_row"] is not None and kwargs["end_row"] <= kwargs["start_row"]:
        arg_parser.error("End row %d must be greater than start row %d" % (kwargs["end_row"], kwargs["start_row"]))

    try:
        table = dxpy.DXGTable(kwargs['reads_table'])
    except:
        raise dxpy.AppError("Failed to open table for export")

    existCols = table.get_col_names()

    ### sort out columns to download

    col = []
    col2 = []

    # if there's a second sequence, it's paired
    if "sequence2" in existCols:
        isPaired = True
    else:
        isPaired = False

{"name": "type", "type": "string"},
            {"name": "strand", "type": "string"},
            {"name": "score", "type": "float"},
            {"name": "is_coding", "type": "boolean"},
            {"name": "parent_id", "type": "int32"},
            {"name": "frame", "type": "int16"},
            {"name": "description", "type": "string"},
            {"name": "source", "type": "string"}]
    
    additionalColumns = []
    for k, v in attributes.iteritems():
        if k not in reservedColumns and len(k) < 100:
            schema.append({"name": k, "type": "string"})
            additionalColumns.append(k)
            
    indices = [dxpy.DXGTable.genomic_range_index("chr","lo","hi", 'gri'), 
               dxpy.DXGTable.lexicographic_index([
                  dxpy.DXGTable.lexicographic_index_column("name", True, False),
                  dxpy.DXGTable.lexicographic_index_column("chr"),
                  dxpy.DXGTable.lexicographic_index_column("lo"),
                  dxpy.DXGTable.lexicographic_index_column("hi"),
                  dxpy.DXGTable.lexicographic_index_column("type")], "search")]
    spansTable = dxpy.new_dxgtable(columns=schema, indices=indices)
    return spansTable, additionalColumns

("lo", "int32"),
               ("hi", "int32"),
               ("name", "string"),
               ("span_id", "int32"),
               ("type", "string"),
               ("strand", "string"),
               ("is_coding", "boolean"),
               ("parent_id", "int32"),
               ("frame", "int16"),
               ("description", "string")]

    column_descs = [dxpy.DXGTable.make_column_desc(name, type) for name, type in columns]
    
    indices = [dxpy.DXGTable.genomic_range_index("chr","lo","hi", 'gri'), 
               dxpy.DXGTable.lexicographic_index([
                  dxpy.DXGTable.lexicographic_index_column("name", True, False),
                  dxpy.DXGTable.lexicographic_index_column("chr"),
                  dxpy.DXGTable.lexicographic_index_column("lo"),
                  dxpy.DXGTable.lexicographic_index_column("hi"),
                  dxpy.DXGTable.lexicographic_index_column("type")], "search")]

    default_row = ["", 0, 0, "", -1, "", ".", False, -1, -1, ""]

    with open(bed_file, 'rU') as bed, dxpy.new_dxgtable(column_descs, indices=indices, mode='w') as span:
        span_table_id = span.get_id()

        details = {"original_contigset": dxpy.dxlink(ref_id)}
        if file_id != None:
            details["original_file"] = dxpy.dxlink(file_id)
        if len(property_keys) != len(property_values):
            raise dxpy.AppError("Expected each provided property to have a corresponding value.")
        for i in range(len(property_keys)):