docs: def as_bulk_queries(queries, bulk_size):
      """Group a iterable of (stmt, args) by stmt into (stmt, bulk_args).
  
      bulk_args will be a list of the args grouped by stmt.
  
      len(bulk_args) will be <= bulk_size
      """
      stmt_dict = defaultdict(list)
      for stmt, args in queries:
          bulk_args = stmt_dict[stmt]
          bulk_args.append(args)
          if len(bulk_args) == bulk_size:
              yield stmt, bulk_args
              del stmt_dict[stmt]
      for stmt, bulk_args in stmt_dict.items():
          yield stmt, bulk_args