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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 find_primitive(self):
 """ Find a primitive version of the unit cell. Returns: A primitive cell in the input cell is searched and returned as an Structure object. If no primitive cell is found, None is returned. """

        lattice, scaled_positions, numbers = spglib.find_primitive(
            self._cell, symprec=self._symprec)

        species = [self._unique_species[i - 1] for i in numbers]

        return Structure(lattice, species, scaled_positions,
                         to_unit_cell=True).get_reduced_structure()