Having error querying and using mutation in graphql - node.js

Question

I am trying to add nested object data to mongodb database using graphql and also fetch the data using the code below
........................................................................................................................................................................................................
const graphql = require('graphql');
const Pricing = require('../models/pricing');
const { GraphQLObjectType, GraphQLString, GraphQLID,
GraphQLInt, GraphQLList, GraphQLNonNull, GraphQLSchema } = graphql;
const PrcingType = new GraphQLObjectType({
name:'Pricing',
fields: () => ({
monthly:{
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
quarterly: {
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
})
});
const RootQuery = new GraphQLObjectType({
name: 'RootQueryType',
fields: {
pricings: {
type: new GraphQLList(PrcingType),
resolve(parent, args){
return Pricing.find({});
},
},
}
});
const Mutation = new GraphQLObjectType({
name: 'Mutation',
fields: {
addPricing: {
type: PrcingType,
args: {
monthly:{
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
quarterly: {
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
},
resolve(parent, args){
let pricing = new Pricing({
monthly:{
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
quarterly: {
starter: {
type: {type: GraphQLString},
},
scale: {
type: {type: GraphQLString},
price: {type: GraphQLString},
},
},
});
return pricing.save();
}
}
}
})
module.exports = new GraphQLSchema({
query: RootQuery,
mutation: Mutation
});
But when I run the grapghql server I get this error
{
"errors": [
{
"message": "The type of Pricing.monthly must be Output Type but got: undefined."
},
{
"message": "The type of Pricing.quarterly must be Output Type but got: undefined."
},
{
"message": "The type of Mutation.addPricing(monthly:) must be Input Type but got: undefined."
},
{
"message": "The type of Mutation.addPricing(quarterly:) must be Input Type but got: undefined."
}
]
}
What am I doing wrong?