title: dbutils.notebook.run not working for mapping arguments
body: <p>Suppose I have 2 notebooks of which the first is the main and the second is for testing.</p>
  
  <p>In the main, I have the following</p>
  
  <pre><code>dbutils.notebook.run("testing", timeoutSeconds = 60, arguments = Map("var" -&gt; "1234"))
  </code></pre>
  
  <p>In testing:</p>
  
  <pre><code>%scala
  println(s"Donut price = $var")
  </code></pre>
  
  <p>And in Main run the notebook. There is error:</p>
  
  <p><a href="https://i.stack.imgur.com/bzl29.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bzl29.jpg" alt="enter image description here"></a></p>