Typical Tests:
min_max([6758, 678, 567, 5]) == (5, 6758) 
min_max([-100, 678, 567, 5]) == (-100, 678) 


Corner Cases:
min_max([1,1,1,1,1,1,1,1]) == (1,1)
min_max([1]) == (1,1)
min_max([]) == None

L = ['a', 0, 2, 'n']
remove_int(L)
assert L == ['a', 'n']

i = 0

L = [0,3]

A = []
for i in range(len(L)):
    if (some_condition(L[i])):
        A.append(True)
    else:
	A.append(False)

for i in range(len(A)).reverse():
	if A[i]:
    		L.pop(i)



def minus(d1, d2): 
	'''(dict, dict) -> NoneType 
	Remove every key in d1 that is also in d2 from d1'''

	L = d1.keys()
	for key in d1.keys():
		if key in d2:
			d1.pop(key)