def virtual_hubs(self):
        """Instance depends on the API version:

           * 2018-04-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_04_01.operations.VirtualHubsOperations>`
           * 2018-06-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_06_01.operations.VirtualHubsOperations>`
           * 2018-07-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_07_01.operations.VirtualHubsOperations>`
           * 2018-08-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_08_01.operations.VirtualHubsOperations>`
        """
        api_version = self._get_api_version('virtual_hubs')
        if api_version == '2018-04-01':
            from .v2018_04_01.operations import VirtualHubsOperations as OperationClass
        elif api_version == '2018-06-01':
            from .v2018_06_01.operations import VirtualHubsOperations as OperationClass
        elif api_version == '2018-07-01':
            from .v2018_07_01.operations import VirtualHubsOperations as OperationClass
        elif api_version == '2018-08-01':
            from .v2018_08_01.operations import VirtualHubsOperations as OperationClass
        else:
            raise NotImplementedError("APIVersion {} is not available".format(api_version))
        return OperationClass(self._client, self.config, Serializer(self._models_dict(api_version)), Deserializer(self._models_dict(api_version)))
Instance depends on the API version:

           * 2018-04-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_04_01.operations.VirtualHubsOperations>`
           * 2018-06-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_06_01.operations.VirtualHubsOperations>`
           * 2018-07-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_07_01.operations.VirtualHubsOperations>`
           * 2018-08-01: :class:`VirtualHubsOperations<azure.mgmt.network.v2018_08_01.operations.VirtualHubsOperations>`