def METHOD_NAME(self) -> None:
    grammar = """
        start: expr NEWLINE? ENDMARKER
        expr: A | B
        A: 'a' | '-'
        B: 'b' | '+'
    """
    self.assertEqual(self.calculate_first_sets(grammar), {
        "A": {"'a'", "'-'"},
        "B": {"'+'", "'b'"},
        "expr": {"'+'", "'a'", "'b'", "'-'"},
        "start": {"'+'", "'a'", "'b'", "'-'"},
    })