title: Error when using Typescript MongoDb Typings (Cannot find namespace)
body: <p>i am trying to use mongodb typings which i installed via </p>
  
  <pre><code>npm install @types/mongodb -D
  </code></pre>
  
  <p>now i want to use the types in a function like that</p>
  
  <pre><code>export default async function insertOne(collection:any, data:any):Promise&lt;InsertOneWriteOpResult&gt; {
    let db = await state.db
    let col = await db.collection(collection)
    let result = await col.insertOne(data)
    return result
  }
  </code></pre>
  
  <p>i am specifically interested in the Type of InsertOneWriteOpResult.
  but i am getting the typescript compiler error:</p>
  
  <pre><code>src/utils/mongodb/collection/insert-one.ts|5 col 17 error| Cannot find namespace 'InsertOneWriteOpResult'.
  </code></pre>
  
  <p>i referenced the typings file in my typings.d.ts</p>
  
  <pre><code>/// &lt;reference path="./../node_modules/@types/mongodb/index.d.ts" /&gt;
  </code></pre>
  
  <p>in this file i can see, that the interface is exported:</p>
  
  <pre><code>export interface InsertOneWriteOpResult {
      insertedCount: number;
      ops: Array&lt;any&gt;;
      insertedId: ObjectID;
      connection: any;
      result: { ok: number, n: number }
  }
  </code></pre>
  
  <p>So my question is, which namespace do i have to use to let typescript check against InsertOptionsWriteOpResult?</p>