az cli throws Unable to load extension 'aks-preview: cannot import name 'SDKProfile'

### **This is autogenerated. Please review and update as needed.**

## In my version of az cli I get the following error
Unable to load extension 'aks-preview: cannot import name 'SDKProfile'

**az upgrade**
`Unknown`

**Errors:**
```
az: 'upgrade' is not in the 'az' command group. See 'az --help'. If the command is from an extension, please make sure the corresponding extension is installed. To learn more about extensions, please visit https://docs.microsoft.com/en-us/cli/azure/azure-cli-extensions-overview
```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- _Put any pre-requisite steps here..._
- `az upgrade --debug`

## Expected Behavior

## Environment Summary
```
Windows-10-10.0.19041-SP0
Python 3.6.6
Installer: MSI

azure-cli 2.8.0

Extensions:
aks-preview 0.5.34

```
## Additional Context