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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 _resolveParam(self, param):
 """ Resolves a param and validates the ownership. :param param: param name or the param instance, which must belong to this Params instance :return: resolved param instance """

        if isinstance(param, Param):
            self._shouldOwn(param)
            return param
        elif isinstance(param, basestring):
            return self.getParam(param)
        else:
            raise ValueError("Cannot resolve %r as a param." % param)