Adds a filter.

        Args:
            structure_filter (StructureFilter): A filter implementating the
                AbstractStructureFilter API. Tells transmuter waht structures
                to retain.

def append_filter(self, structure_filter):
        """
        Adds a filter.

        Args:
            structure_filter (StructureFilter): A filter implementating the
                AbstractStructureFilter API. Tells transmuter waht structures
                to retain.
        """
        hdict = structure_filter.as_dict()
        hdict["input_structure"] = self.final_structure.as_dict()
        self.history.append(hdict)