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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 structures(self):
 """ Copy of all structures in the TransformedStructure. A structure is stored after every single transformation. """

        hstructs = [Structure.from_dict(s['input_structure'])
                    for s in self.history if 'input_structure' in s]
        return hstructs + [self.final_structure]