How to use the @graphback/core.GraphbackOperationType.DELETE function in @graphback/core

return this.service.create(objectName, args.input, {
            publishEvent: resolverElement.config.subCreate
          }, context)
        }
      }
      if (resolverElement.config.update) {
        const updateField = getFieldName(resolverElement.name, GraphbackOperationType.UPDATE);
        // tslint:disable-next-line: no-any
        resolvers.Mutation[updateField] = (parent: any, args: any, context: any) => {
          return this.service.update(objectName, args.id, args.input, {
            publishEvent: resolverElement.config.subUpdate
          }, context)
        }
      }
      if (resolverElement.config.delete) {
        const deleteField = getFieldName(resolverElement.name, GraphbackOperationType.DELETE);
        // tslint:disable-next-line: no-any
        resolvers.Mutation[deleteField] = (parent: any, args: any, context: any) => {
          return this.service.delete(objectName, args.id, args.input, {
            publishEvent: resolverElement.config.subDelete
          }, context)
        }
      }

      if (resolverElement.config.findAll) {
        const findAllField = getFieldName(resolverElement.name, GraphbackOperationType.FIND_ALL, 's');
        // tslint:disable-next-line: no-any
        resolvers.Query[findAllField] = (parent: any, args: any, context: any) => {
          return this.service.findAll(objectName, context)
        }
      }
      if (resolverElement.config.find) {

export const deleteMutation = (t: InputModelTypeContext, ) => {
  const fieldName = getFieldName(t.name, GraphbackOperationType.DELETE)

  return `mutation ${fieldName}($id: ID!) {
    ${fieldName}(id: $id)
  }
`
}

const deleteMutationTS = (t: InputModelTypeContext, imports: string) => {
  const fieldName = getFieldName(t.name, GraphbackOperationType.DELETE)

  return `${imports}

export const ${fieldName} = gql\`
  ${deleteMutation(t)}

  \$\{${t.name}Fragment}
\`
`
}

mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.CREATE),
        implementation: createMutation(t)
      })
    }

    if (t.config.update) {
      mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.UPDATE),
        implementation: updateMutation(t)
      })
    }

    if (t.config.delete) {
      mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.DELETE),
        implementation: deleteMutation(t)
      })
    }
  })

.map((t: InputModelTypeContext) => {
      const fieldName = getFieldName(t.name, GraphbackOperationType.DELETE)

      return `${fieldName}(id: ID!): ID!`
    })
}

mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.CREATE),
        implementation: createMutationTS(t, imports)
      })
    }

    if (t.config.update) {
      mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.UPDATE),
        implementation: updateMutationTS(t, imports)
      })
    }

    if (t.config.delete) {
      mutations.push({
        name: getFieldName(t.name, GraphbackOperationType.DELETE),
        implementation: deleteMutationTS(t, imports)
      })
    }
  })

const deleteResolver = (t: InputModelTypeContext): string | undefined => {
  if (t.config.delete) {
    return templates.deleteTemplate(getFieldName(t.name, GraphbackOperationType.DELETE), t.name, t.config.subDelete)
  }

  return undefined
}

public subscribeToDelete(name: string, context?: GraphbackRuntimeContext): AsyncIterator | undefined {
        if (!this.pubSub) {
            this.logger.log(`Cannot subscribe to events for ${name}`)

            throw Error(`Missing PubSub implementation in CRUDService`);
        }
        const deleteSubKey = subscriptionTopicMapping(GraphbackOperationType.DELETE, name);

        return this.pubSub.asyncIterator(deleteSubKey)
    }