Support datetime.timedelta for target_window in get_memento()

[Mr0grog]

The WaybackClient.get_memento() method has a target_window parameter, which is used when a memento does not exist at the requested time. If the parameter exact=False, get_memento() returns the nearest-in-time memento, but only if it is within the number of seconds specified in target_window.

wayback/wayback/_client.py

Lines 717 to 719 in c066e04

	def get_memento(self, url, datetime=None, mode=Mode.original, *,
	exact=True, exact_redirects=None,
	target_window=24 * 60 * 60, follow_redirects=True):

Since Python has a built in datetime.timedelta type to represent exactly this kind of concept, we should also accept it instead of an integer for target_window. (Really, I’m not sure why we didn’t do this originally!)

[Mr0grog]

This is useful because it provides a more readable way to set timeframes. For example:

# 4 hour window as an integer:
get_memento(url, exact=False, target_window=4 * 60 * 60)

# 4 hour window as a timedelta:
get_memento(url, exact=False, target_window=timedelta(hours=4))