title: Mongoose insertMany() return callback is not a function error while passing options
body: <p>I am using mongoose <strong>version 4.7.2</strong> and need to insert a bulk amount of data into a collection without duplicates and validation errors as a <strong>promise</strong> . </p>
  
  <p>Code :</p>
  
  <pre><code>  module.exports.addCustomers = function (customers) {
     return Customer.insertMany(customers,{ordered :false})
     }
  </code></pre>
  
  <p>While trying to insert the documents using insertMany() the following error occurred.</p>
  
  <p><strong>TypeError: callback is not a function</strong></p>
  
  <p><a href="https://i.stack.imgur.com/iOqop.png" rel="nofollow noreferrer">Error in console</a></p>
  
  <p>There is no error when I remove  {ordered :false} from my code.</p>