prefix_with("TEXT") adds arbitrary text between INSERT and the rest of the SQL. execute() accepts a list of dictionaries with the records you would like to insert or a single dictionary if you only want to insert a single record.
The SQLite syntax for the behavior you’re looking for:
inserter = table_object.insert().prefix_with("OR REPLACE")
inserter.execute([{'column1':'value1'}, {'column1':'value2'}])