def test_blood_with_empty_string(self):
		self.assertFalse(Donor.is_valid_blood_type(''))
	def test_blood_with_number(self):
		self.assertFalse(Donor.is_valid_blood_type('99'))
	def test_blood_with_valid_string_upper(self):
		self.assertTrue(Donor.is_valid_blood_type('A+'))