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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 get_extended_surface_mesh(self, repeat=(5, 5, 1)):
 """ Gets an extended surface mesh for to use for adsorption site finding by constructing supercell of surface sites Args: repeat (3-tuple):
 repeat for getting extended surface mesh """

        surf_str = Structure.from_sites(self.surface_sites)
        surf_str.make_supercell(repeat)
        return surf_str