test.py

import graphene

class Query(graphene.ObjectType):
    hello = graphene.String(name=graphene.Argument(
        graphene.String, default_value="stranger"), age=graphene.Argument(graphene.Int))

    def resolve_hello(self, args, context, info):
        return 'Hello {} you are {} years old'.format(args['name'], args['age'])

def main():
    schema = graphene.Schema(query=Query)
    result = schema.execute('{ hello(name: "bob", age: 13) }')
    print(result.data['hello'])


if __name__ == "__main__":
    main()