def test_list_1(self):
data = [1, 2, 3, 1, 54, -56, -8521, 4156, 947]
result = maximal_element(data)
self.assertEqual(result, 7)
def test_list_6(self):
data = [1146541, 213, -4546156, 0, 15]
result = maximal_element(data)
self.assertEqual(result, 0)
def test_list_4(self):
data = [1, 1, 1, 1, 1]
result = maximal_element(data)
self.assertEqual(result, 0)
def test_list_5(self):
data = [1, -1651, 0, 16, 45, -6864, 23, 3564]
result = maximal_element(data)
self.assertEqual(result, 7)
def test_list_2(self):
data = []
result = maximal_element(data)
self.assertEqual(result, -1)