@staticmethod
    def _infimum_key(expr):
        """
        Return infimum (if possible) else S.Infinity.
        """
        try:
            infimum = expr.inf
            assert infimum.is_comparable
        except (NotImplementedError,
                AttributeError, AssertionError, __HOLE__):
            infimum = S.Infinity
        return infimum
dataset/ETHPy150Open sympy/sympy/sympy/sets/sets.py/Set._infimum_key