The <yield> keyword can turn any function into a generator. It works like a standard return keyword. But it’ll always return a generator object. Also, a function can have multiple calls to the <yield> keyword.

See the example below.

def testgen(index):

weekdays = ['sun','mon','tue','wed','thu','fri','sat']

yield weekdays[index]

yield weekdays[index+1]

day = testgen(0)

print next(day), next(day)

#output: sun mon