import the graphql schema from else where?

[stnbSim]

Great example.
Just wonder if it is possible to import the schema from a *.graphql instead of write a plain text in template.yaml directly.

HelloWorldApiSchema:
    Type: "AWS::AppSync::GraphQLSchema"
    Properties:
      ApiId: !GetAtt HelloWorldApi.ApiId
      Definition: |
        schema {
          query: Query
        }
        type HelloWorld {
          go: String
          node: String
          python: String
          ruby: String
        }
        type Query {
          getHelloWorld: HelloWorld
        }

Thank you