GraphQL mutation issue with Enum

I have object something like below:

type SomeEventInput {
  event: Event 
}

type Event {
  type: EventType! 
}

enum EventType {
MORNING
EVENING
AFTERNOON
MIDNIGHT
}

Mutation.SomeEvent(input: SomeEventInput!): Boolean!

What i am trying to test it something like :

mutation SomeEvent($input: SomeEventInput!) {
    SomeEventInput(input: {Event: {type: MORNING}})
}

But it is showing error for

"message": "Variable "$input" is never used in operation "SomeEvent".",