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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 _resolve_value(self, name):
 """ Returns an appropriate value for the given name. This simply asks each of the instances for a value. """

        for instance in self.__instances():
            value = instance._resolve_value(name)
            if value:
                return value

        # Otherwise, return an appropriate default value (populate_from)
        # TODO: This is duplicated in meta_models. Move this to a common home.
        if name in self.__metadata._meta.elements:
            populate_from = self.__metadata._meta.elements[name].populate_from
            if callable(populate_from):
                return populate_from(None)
            elif isinstance(populate_from, Literal):
                return populate_from.value
            elif populate_from is not NotSet:
                return self._resolve_value(populate_from)