List and isinstance

[Roh_80]

numbers = [1, 2, 3,[4,5,6]]`
for i in numbers:`
	if isinstance(i,list):`
		`print("YES")`		
	else:
		print("NO")`

1. when 1 = 1 , why it ins't an instance of list ? It is a nested list and 1 is definitely an element of outer list.
2. When i becomes 4 , output is YES. It is an inner list so why the same logic was not implemented for when i = 1.