CF Resource which API Gateway integrate stepfunction

{
  "APIAssumeRolePolicyDocument": {
    "Type": "AWS::IAM::Role",
    "Properties": {
      "AssumeRolePolicyDocument": {
        "Version": "2012-10-17",
        "Statement": [
          {
            "Effect": "Allow",
            "Principal": {
              "Service": "apigateway.amazonaws.com"
            },
            "Action": "sts:AssumeRole"
          }
        ]
      },
      "Policies": [
        {
          "PolicyName": "apigatewaytostepfunctions",
          "PolicyDocument": {
            "Version": "2012-10-17",
            "Statement": [
              {
                "Effect": "Allow",
                "Action": [
                  "states:StartExecution"
                ],
                "Resource": "*"
              }
            ]
          }
        }
      ]
    }
  },
  "ApiGatewayRestApi": {
    "Type": "AWS::ApiGateway::RestApi",
    "Properties": {
      "Name": "dev-step-function"
    }
  },
  "ApiGatewayResourcePanpan": {
    "Type": "AWS::ApiGateway::Resource",
    "Properties": {
      "ParentId": {
        "Fn::GetAtt": [
          "ApiGatewayRestApi",
          "RootResourceId"
        ]
      },
      "PathPart": "panpan",
      "RestApiId": {
        "Ref": "ApiGatewayRestApi"
      }
    }
  },
  "ApiGatewayMethodPanpanGet": {
    "Type": "AWS::ApiGateway::Method",
    "Properties": {
      "HttpMethod": "POST",
      "RequestParameters": {},
      "ResourceId": {
        "Ref": "ApiGatewayResourcePanpan"
      },
      "RestApiId": {
        "Ref": "ApiGatewayRestApi"
      },
      "AuthorizationType": "NONE",
      "Integration": {
        "IntegrationHttpMethod": "POST",
        "Type": "AWS",
        "Credentials": {
          "Fn::GetAtt" : [
            "APIAssumeRolePolicyDocument",
            "Arn"
          ]
        },
        "Uri": {
          "Fn::Join": [
            "",
            [
              "arn:aws:apigateway:",
              {
                "Ref": "AWS::Region"
              },
              ":states:action/StartExecution"
            ]
          ]
        },
        "PassthroughBehavior": "NEVER",
        "RequestTemplates": {
          "application/json": {
            "Fn::Join" : [
              "", [
                "#set( $body = $util.escapeJavaScript($input.json('$')) ) \n\n{\"input\": \"$body\",\"name\": \"$context.requestId\",\"stateMachineArn\":\"",
                {
                  "Ref": "MyStateMachine1StepFunctionsStateMachine"
                },
                "\"}"
              ]
            ]
          }

        },
        "IntegrationResponses": [
            {
              "StatusCode": 200,
              "SelectionPattern": "",
              "ResponseParameters": {},
              "ResponseTemplates": {}
            },
            {
              "StatusCode": 400,
              "SelectionPattern": "[\\s\\S]*\\[400\\][\\s\\S]*",
              "ResponseParameters": {},
              "ResponseTemplates": {}
            }
          ]
      },
      "MethodResponses": [
        {
            "ResponseParameters": {},
            "ResponseModels": {},
            "StatusCode": 200
        },
        {
            "ResponseParameters": {},
            "ResponseModels": {},
            "StatusCode": 400
        }
      ]
    }
  },
  "ApiGatewayDeployment14917816s7ff278": {
    "Type": "AWS::ApiGateway::Deployment",
    "Properties": {
      "RestApiId": {
        "Ref": "ApiGatewayRestApi"
      },
      "StageName": "dev"
    },
    "DependsOn": [
      "ApiGatewayMethodPanpanGet"
    ]
  }
}