def test_zero_division():
assert press_sequence('5 / 0 =') == 'Error'
def test_input_decimals():
assert press_sequence('0 . 2 * 0 . 5 =') == '0.1'
def test_input_clear_screen():
assert press_sequence('1 + 2 AC') == ''
def test_input_negneg():
assert press_sequence('- 1 - - 2 =') == '1'
def test_input_sub():
assert press_sequence('5 - 1 5 =') == '-10'
def test_input_sum():
assert press_sequence('1 + 2 =') == '3'