Как сравнить строку и datetime?

from datetime import datetime
chday = datetime.strptime('datetime.date(2018, 12, 31)', 'datetime.date(%Y, %m, %d)')
today = datetime.today()
print(today < chday)
print(today > chday)
print(today == chday)
type(chday)

True
False
False
<class 'datetime.datetime'>

>>> import datetime
>>> in_str = "datetime.date(2018, 12, 11)"
>>> type(in_str)
<class 'str'>
>>> res = eval(in_str)
>>> res
datetime.date(2018, 12, 11)
>>> type(res)
<class 'datetime.date'>