def test_front():
l = SingleLinkedList()
for i in range(10):
l.push_back(i)
assert 0 == l.front()
l = SingleLinkedList()
for i in range(10):
l.push_front(i)
assert i == l.front()
def test_front():
l = SingleLinkedList()
for i in range(10):
l.push_back(i)
assert 0 == l.front()
l = SingleLinkedList()
for i in range(10):
l.push_front(i)
assert i == l.front()