mock_open does not support the use of 'seek()'

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-05-10.11:32:27.597>
labels = ['type-feature', 'library', '3.11']
title = "mock_open does not support the use of 'seek()'"
updated_at = <Date 2021-05-10.12:47:20.257>
user = 'https://bugs.python.org/nikle'

bugs.python.org fields:

activity = <Date 2021-05-10.12:47:20.257>
actor = 'xtreak'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-05-10.11:32:27.597>
creator = 'nikle'
dependencies = []
files = []
hgrepos = []
issue_num = 44102
keywords = []
message_count = 2.0
messages = ['393378', '393383']
nosy_count = 7.0
nosy_names = ['rbcollins', 'cjw296', 'michael.foord', 'lisroach', 'mariocj89', 'xtreak', 'nikle']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue44102'
versions = ['Python 3.11']