How to use the pglast.printer.IndentedStream function in pglast

def test_prettification(src, lineno, case):
    parts = case.split('\n=\n')
    original = parts[0].strip()
    parts = parts[1].split('\n:\n')
    expected = parts[0].strip().replace('\\n\\\n', '\n')
    if len(parts) == 2:
        options = literal_eval(parts[1])
    else:
        options = {}
    prettified = IndentedStream(**options)(original)
    assert expected == prettified, "%s:%d:%r != %r" % (src, lineno, expected, prettified)

def test_prettification(sample):
    parts = sample.split('\n=\n')
    original = parts[0].strip()
    parts = parts[1].split('\n:\n')
    expected = parts[0].strip()
    if len(parts) == 2:
        options = literal_eval(parts[1])
    else:
        options = {}
    prettified = IndentedStream(**options)(original)
    assert expected == prettified, "%r != %r" % (expected, prettified)

def roundtrip(sql):
    orig_ast = parse_sql(sql)
    _remove_stmt_len_and_location(orig_ast)

    serialized = RawStream()(Node(orig_ast))
    try:
        serialized_ast = parse_sql(serialized)
    except:  # noqa
        raise RuntimeError("Could not reparse %r" % serialized)
    _remove_stmt_len_and_location(serialized_ast)
    assert orig_ast == serialized_ast, "%r != %r" % (sql, serialized)

    indented = IndentedStream()(Node(orig_ast))
    try:
        indented_ast = parse_sql(indented)
    except:  # noqa
        raise RuntimeError("Could not reparse %r" % indented)
    _remove_stmt_len_and_location(indented_ast)
    assert orig_ast == indented_ast, "%r != %r" % (sql, indented)

    # Run ``pytest -s tests/`` to see the following output
    print()
    print(indented)

def test_indented_stream_with_sql():
    raw_stmt_printer = printer.NODE_PRINTERS.pop('RawStmt', None)
    try:
        @printer.node_printer('RawStmt')
        def raw_stmt(node, output):
            output.write('Yeah')

        output = printer.IndentedStream()
        result = output('SELECT 1; SELECT 2')
        assert result == 'Yeah;\n\nYeah'

        output = printer.IndentedStream(separate_statements=False)
        result = output('SELECT 1; SELECT 2')
        assert result == 'Yeah;\nYeah'
    finally:
        if raw_stmt_printer is not None:
            printer.NODE_PRINTERS['RawStmt'] = raw_stmt_printer
        else:
            printer.NODE_PRINTERS.pop('RawStmt', None)