def test_t(): assert main.complementary('T') == 'A'
def test_a(): assert main.complementary('A') == 'T'
def test_c(): assert main.complementary('C') == 'G'
def test_complete(): assert main.complementary('ATGC') == 'TACG'
def test_g(): assert main.complementary('G') == 'C'