I'm having some trouble generating types for my custom binding. I'm pretty much following (I think) the example in the docs about creating a class that extends from

Binding

(where I differ is that I'm getting my schema by converting the downloaded introspection result json to SDL with buildClientSchema + printSchema) then I call

npx graphql-binding --language typescript --input schema.ts --outputBinding binding.ts

and get

TypeError: this.schema.getQueryType is not a function
    at TypescriptGenerator.renderQueries (node_modules/graphql-binding/src/codegen/TypescriptGenerator.ts:180:35)
    at TypescriptGenerator.render (node_modules/graphql-binding/src/codegen/TypescriptGenerator.ts:144:31)
    at node_modules/graphql-binding/src/bin.ts:58:34
    at step (node_modules/graphql-binding/dist/bin.js:41:23)
    at Object.next (node_modules/graphql-binding/dist/bin.js:22:53)
    at node_modules/graphql-binding/dist/bin.js:16:71
    at Promise (<anonymous>)
    at __awaiter (node_modules/graphql-binding/dist/bin.js:12:12)
    at run (node_modules/graphql-binding/dist/bin.js:81:12)
    at Object.<anonymous> (node_modules/graphql-binding/src/bin.ts:40:1)