datetime.strptime not accepts single-digit months and days for %m and %d

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-06-22.13:03:38.217>
labels = ['type-bug', 'library']
title = 'datetime.strptime not able to recognize invalid date formats'
updated_at = <Date 2018-07-05.15:00:50.065>
user = 'https://bugs.python.org/RaghunathLingutla'

bugs.python.org fields:

activity = <Date 2018-07-05.15:00:50.065>
actor = 'p-ganssle'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-06-22.13:03:38.217>
creator = 'Raghunath Lingutla'
dependencies = []
files = []
hgrepos = []
issue_num = 33941
keywords = []
message_count = 3.0
messages = ['320233', '320245', '320291']
nosy_count = 4.0
nosy_names = ['belopolsky', 'crwilcox', 'p-ganssle', 'Raghunath Lingutla']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue33941'
versions = ['Python 2.7', 'Python 3.6']