def test_nullable_string_empty(self): self.assertIsNone(Loader.nullable_string(""))
def test_nullable_string_whitespace(self): self.assertIsNone(Loader.nullable_string(" "))
def test_nullable_string(self): self.assertEqual(Loader.nullable_string("BANK"), "BANK")
def test_nullable_string_whitespace(self): self.assertIsNone(Loader.nullable_string(' '))
def test_nullable_string_empty(self): self.assertIsNone(Loader.nullable_string(''))
def test_nullable_string(self): self.assertEqual(Loader.nullable_string('BANK'), 'BANK')