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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 from_snl(cls, snl):
 """ Create TransformedStructure from SNL. Args: snl (StructureNL):
 Starting snl Returns: TransformedStructure """

        hist = []
        for h in snl.history:
            d = h.description
            d['_snl'] = {'url': h.url, 'name': h.name}
            hist.append(d)
        return cls(snl.structure, history=hist)