How to use the apollo-graphql.modulesFromSDL function in apollo-graphql

//
  let shapedModulesOrSDL: (GraphQLSchemaModule | DocumentNode)[] | DocumentNode;
  if ('typeDefs' in modulesOrSDL) {
    const { typeDefs, resolvers } = modulesOrSDL;
    const augmentedTypeDefs = Array.isArray(typeDefs) ? typeDefs : [typeDefs];
    shapedModulesOrSDL = augmentedTypeDefs.map((typeDefs, i) => {
      const module: GraphQLSchemaModule = { typeDefs };
      // add the resolvers to the first "module" in the array
      if (i === 0 && resolvers) module.resolvers = resolvers;
      return module;
    });
  } else {
    shapedModulesOrSDL = modulesOrSDL;
  }

  const modules = modulesFromSDL(shapedModulesOrSDL);

  let schema = buildSchemaFromSDL(
    modules,
    new GraphQLSchema({
      query: undefined,
      directives: [...specifiedDirectives, ...federationDirectives],
    }),
  );

  // At this point in time, we have a schema to be printed into SDL which is
  // representative of what the user defined for their schema. This is before
  // we process any of the federation directives and add custom federation types
  // so its the right place to create our service definition sdl.
  //
  // We have to use a modified printSchema from graphql-js which includes
  // support for preserving the *uses* of federation directives while removing