CloudFormation: extraneous key [DependsOn] is not permitted - amazon-web-services

Question

Building a simple Hello World API using SAM(API Gateway + Lambda). I was told DependsOn is supposed to work with all resources.
The APIs were configured as :
HelloWorldAPI:
Type: AWS::Serverless::Api
# Type: AWS::ApiGateway::RestApi
Properties:
Name: HelloWorldApi
StageName: !Ref StageName
HelloWorldAPIResource:
Type: AWS::ApiGateway::Resource
Properties:
RestApiId: !Ref HelloWorldAPI
ParentId: !GetAtt HelloWorldAPI.RootResourceId
PathPart: hello
HelloWorldAPIMethod:
Type: AWS::ApiGateway::Method
Properties:
AuthorizationType: NONE
HttpMethod: GET
ResourceId: !Ref HelloWorldAPIResource
RestApiId: !Ref HelloWorldAPI
Integration:
Type: AWS_PROXY
IntegrationHttpMethod: GET
Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${HelloWorldFunction.Arn}/invocations
# - Arn: !GetAtt HelloWorldFunction.Arn
HelloWorldAPIDeployment:
Type: AWS::ApiGateway::Deployment
Properties:
RestApiId: !Ref HelloWorldAPI
StageName: !Ref StageName
DependsOn:
- HelloWorldAPIMethod
But I get the following errors during deployment:
CREATE_FAILED AWS::ApiGateway::Deployment HelloWorldAPIDeployment Properties validation failed for resource
HelloWorldAPIDeployment with message: #:
extraneous key [DependsOn] is not permitted
CREATE_FAILED AWS::ApiGateway::Resource HelloWorldAPIResource Resource creation cancelled
CREATE_FAILED AWS::ApiGateway::Deployment HelloWorldAPIDeployment5332c373d4 Resource handler returned message: "The REST
API doesn't contain any methods (Service:
ApiGateway, Status Code: 400, Request ID:
634b4de5-ead7-48f5-8075-ab55d7176189,
Extended Request ID: null)" (RequestToken:
ef65a5fd-cdf4-fe14-2010-a513bca36aca,
HandlerErrorCode: InvalidRequest)
The explicitly defined AWS::ApiGateway::Deployment is unable to use DependsOn, while there is another AWS::ApiGateway::Deployment being created implicitly but unnecessarily which is being deployed before the method, which was the reason I defined one explicitly in the first place.
Any help is appreciated.

Answer 1

DependsOn should have one last tab less:
HelloWorldAPIDeployment:
Type: AWS::ApiGateway::Deployment
Properties:
RestApiId: !Ref HelloWorldAPI
StageName: !Ref StageName
DependsOn:
- HelloWorldAPIMethod