title: Error: "Values must match the following regular expression"
body: <p>I'm playing with the Youtube Analytics API Explorer and I have no problem until I try to put several metrics in the "Metrics" field.</p>
  
  <p>They ask especifically to enter data in this format </p>
  
  <blockquote>
    <p>A comma-separated list of YouTube Analytics metrics, such as views or likes,dislikes.</p>
  </blockquote>
  
  <p>So I try with this:</p>
  
  <blockquote>
    <p>views, likes, shares</p>
  </blockquote>
  
  <p>But then I get this message:</p>
  
  <blockquote>
    <p>"Invalid value 'shares,+ comments+'. Values must match the following regular expression: '[0-9a-zA-Z,]+'"</p>
  </blockquote>
  
  <p>What am I doing wrong? :'(</p>