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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_region(region, mesh_in, save_edges=False, save_faces=False, localize=False, is_surface=False):
 """ Create a mesh corresponding to a given region. """

        mesh = Mesh( mesh_in.name + "_reg" )
        mesh.coors = mesh_in.coors.copy()
        mesh.ngroups = mesh_in.ngroups.copy()

        mesh.conns = []
        mesh.descs = []
        mesh.mat_ids = []

        if not is_surface:
            if region.has_cells():
                for ig in region.igs:
                    mesh.descs.append( mesh_in.descs[ig] )
                    els = region.get_cells( ig )
                    mesh.mat_ids.append( mesh_in.mat_ids[ig][els,:].copy() )
                    mesh.conns.append( mesh_in.conns[ig][els,:].copy() )

            if save_edges:
                ed = region.domain.ed
                for ig in region.igs:
                    edges = region.get_edges( ig )
                    mesh.descs.append( '1_2' )
                    mesh.mat_ids.append( ed.data[edges,0] + 1 )
                    mesh.conns.append( ed.data[edges,-2:].copy() )

            if save_faces:
                mesh._append_region_faces(region)

            if save_edges or save_faces:
                mesh.descs.append( {2 : '2_3', 3 : '3_4'}[mesh_in.dim] )
                mesh.mat_ids.append( -nm.ones_like( region.all_vertices ) )
                mesh.conns.append(make_point_cells(region.all_vertices,
                                                   mesh_in.dim))

        else:
            mesh._append_region_faces(region, force_faces=True)

        mesh._set_shape_info()

        if localize:
            mesh.localize( region.all_vertices )

        return mesh