def test_flexi_items():
f = Flexi()
f["alice"] = 10
f["bob"] = 20
f["carol"] = 30
f["dave"] = 40
assert len(f.items()) == 4
def test_flexi_popitem():
f = Flexi()
f["alice"] = 10
f["bob"] = 20
f["carol"] = 30
f["dave"] = 40
p = f.popitem()
assert len(f.items()) == 3
assert p == ("dave", 40)