Create a class that inherits `ITokenExtensionGrant`, and then register it with the framework.
In the `MyTokenExtensionGrant` class below we try to get the token details. The `ForbidResult` handles the failure case and `SignInResult` returns a new token response.
Create a class that inherits `ITokenExtensionGrant`, and then register it with the framework.
You can pass more parameters to implement business checks.
In the `MyTokenExtensionGrant` class below we try to get the token details, The `ForbidResult` handles the failure case and `SignInResult` returns a new token response, You can pass more parameters to implement business checks.
```cs
public class MyTokenExtensionGrant : ITokenExtensionGrant