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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def remove(self, element):
 """ Return a new PSet with element removed. Raises KeyError if element is not present. pset([1]) """

        if element in self._map:
            return self.evolver().remove(element).persistent()

        raise KeyError("Element '%s' not present in PSet" % element)