def test_dna_starts_with_self():
  dna = 'actgt'
  assert dna_starts_with(dna,dna)
def test_dna_starts_with_single_char():
  assert dna_starts_with('actgt','a')
def test_dna_not_starts_with_single_char():
  assert not dna_starts_with('actgt','t')