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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 status(self):
 """Return string indicating the error encountered on failure."""

        self._check_valid()
        if self._ret_val == swiglpk.GLP_ENOPFS:
            return 'No primal feasible solution'
        elif self._ret_val == swiglpk.GLP_ENODFS:
            return 'No dual feasible solution'
        return str(swiglpk.glp_get_status(self._problem._p))