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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 virtual_media(self):
 """Property to provide reference to `VirtualMediaCollection` instance. It is calculated once when the first time it is queried. On refresh, this property gets reset. """

        return virtual_media.VirtualMediaCollection(
            self._conn, utils.get_subresource_path_by(self, 'VirtualMedia'),
            redfish_version=self.redfish_version)