def METHOD_NAME(lexer, examples, expected_token_type):
    for test_number, example in enumerate(examples.split(), 1):
        token_count = 0
        for token_type, token_value in lexer.get_tokens(example):
            if token_type != Whitespace:
                token_count += 1
                assert token_type == expected_token_type, \
                    'token_type #%d for %s is be %s but must be %s' % \
                    (test_number, token_value, token_type, expected_token_type)
        assert token_count == 1, \
            '%s must yield exactly 1 token instead of %d' % \
            (example, token_count)