Apollo客户端在向服务器发送突变时返回“400（错误请求）错误”

我目前正在为Apollo客户端使用vue-apollo包，并为我的GraphQl API使用带有django和graphene-python的VueJs堆栈。

我在下面用vue-apollo进行了简单的设置：

import Vue from 'vue'
import { ApolloClient } from 'apollo-client'
import { HttpLink } from 'apollo-link-http'
import { InMemoryCache } from 'apollo-cache-inmemory'
import VueApollo from 'vue-apollo'
import COOKIEs from 'js-COOKIE'


const httpLink = new HttpLink({
  credentials: 'same-origin',
  uri: 'http://localhost:8000/api/',
})

// Create the apollo client
const apolloClient = new ApolloClient({
  link: httpLink,
  cache: new InMemoryCache(),
  connectToDevTools: true,
})

export const apolloProvider = new VueApollo({
  defaultClient: apolloClient,
})

// Install the vue plugin
Vue.use(VueApollo)

'''

import gql from "graphql-tag";
import CREATE_USER from "@/graphql/NewUser.gql";

export default {
  data() {
    return {
      test: ""
    };
  },
  methods: {
    authenticateUser() {
      this.$apollo.mutate({
        mutation: CREATE_USER,
        variables: {
          email: "test@example.com",
          password: "pa$$word",
          username: "testuser"
        }
      }).then(data => {
          console.log(result)
      })
    }
  }
};

mutation createUser($email: String!, $password: String!, $username: String!) {
  createUser (username: $name, password: $password, email: $email)
  user {
    id
    username
    email
    password
  }
}

POST http://localhost:8000/api/ 400 (Bad Request)

ApolloError.js?d4ec:37 Uncaught (in promise) Error: Network error: Response not successful: Received status code 400