def is_prime(x):
	#your code here
	return ____

def sum_cubes(n):
	#your code here
	return ____

def fibonacci3(n):
	#your code here
	return ____

def polymax(xmin, xmax, ymin, ymax):
	#your code here
	return ____

def collatz(x):
	#your code here
	return ____