Timestamps are the representation of a date in the number of seconds from a specific moment. Usually, as the value that a computer can represent is limited in size, that is normally taken from January 1st, 1970.
If you ever received a value such as 1521588268
as a datetime representation, you might be wondering how that can be converted into an actual datetime.
Most recent Python versions introduced a method to quickly convert datetimes back and forth from timestamps:
>>> import datetime
>>> ts = 1521588268
>>> d = datetime.datetime.utcfromtimestamp(ts)
>>> print(repr(d))
datetime.datetime(2018, 3, 20, 23, 24, 28)
>>> newts = d.timestamp()
>>> print(newts)
1521584668.0