import re
restring = "(Watch|Put on) (?P<videotitle>[^\s]+)(?: season )?(?P<seasonnumber>[\d]+)?(?: episode )?(?P<episodenumber>[\d]+)?"
mstring1 = "Watch abcdefg season 4 episode 2"
mstring2 = "Watch arseholes"
r1 = re.search(restring,mstring1)
r2 = re.search(restring,mstring2)
print "for: Watch abcdefg season 4 episode 2"
for n in r1.groups():
print n
print "for: Watch arseholes"
for n in r2.groups():
print n