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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 set_centralized_assembled_rows_cols(self, irn, jcn):
 """Set assembled matrix indices on processor 0. The row and column indices (irn & jcn) should be one based. """

        if self.myid != 0:
            return
        assert irn.size == jcn.size
        self._refs.update(irn=irn, jcn=jcn)
        self.id.nz = irn.size
        self.id.irn = self.cast_array(irn)
        self.id.jcn = self.cast_array(jcn)