Several improvement point of gdbm module

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-10-17.11:35:30.222>
labels = ['type-feature', 'library', '3.11']
title = 'Several improvement point of gdbm module'
updated_at = <Date 2021-10-17.11:35:45.741>
user = 'https://github.com/corona10'

bugs.python.org fields:

activity = <Date 2021-10-17.11:35:45.741>
actor = 'corona10'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-10-17.11:35:30.222>
creator = 'corona10'
dependencies = []
files = []
hgrepos = []
issue_num = 45503
keywords = []
message_count = 1.0
messages = ['404136']
nosy_count = 3.0
nosy_names = ['methane', 'serhiy.storchaka', 'corona10']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue45503'
versions = ['Python 3.11']