Answer by Marat for using filter and generator to generator endless prime number in python

First, filter over iterator returns another iterator. I.e. when we do something like:

it = filter(_not_divisible(3), it)it = filter(_not_divisible(5), it)

We get a chained iterator "odd number AND not divisible by 3 AND not divisible by 5". It is somewhat similar to chained decorators, where we get an equivalent of:

# assuming we have decorator @not divisible@not_divisible(2)def iter():    return xrange(inf)# then, at every subsequent prime we do something like:iter = not_divisible(3)(iter)# next prime is 5:iter = not_divisible(5)(iter)

... and so on