Add a textual representation of terminals and nonterminals for the sake of debugging

    def __hash__(self):

        return hash(self.name)

    def __repr__(self) -> str:

        return f"Terminal({self.name})"

class Nonterminal:

    def __init__(self, name: str):

    def __lt__(self, other) -> bool:

        return self.name < other.name

    def __repr__(self) -> str:

        return f"Nonterminal({self.name})"

class Character:

    def __init__(self, name: str):