class Conjunto:
    """Representa una lista de elementos que no se repiten."""
    def __init__(self):
        self.__conj = []
    ...
 
    def __add(self, val):
        self.__conj.append(val)
    ...
 
    def __str__(self):
        return str.join(", ", [str(x) for x in self.__conj])
    ...
 
    def __chk_invariante(self):
        for i, x in enumerate(self.__conj):
            cdr = self.__conj[i + 1:]
            if x in cdr:
                raise ValueError(f"{x} repetido en: {cdr.index(x) + i + 1}")
            ...
        ...
    ...
 
    def __getattr__(self, str_m):
        if str_m == "add":
        	# Utiliza tuplas para invocar dos fuciones desde la lambda,
        	# devolviendo el retorno de la primera.
            return lambda val: (self.__add(val), self.__chk_invariante())[0]
        ...
 
        raise AttributeError(f"{self.__class__.__name__}.{str_m}??")
    ...
...
 
 
if __name__ == "__main__":
    c1 = Conjunto()
    c1.add(1)
    c1.add(2)
    c1.add(2)
    print(c1)
...
 

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