title: Convert multiple isinstance checks to structural pattern matching
body: <p>I want to convert this existing code to use pattern matching:</p>
  <pre><code>if isinstance(x, int):
      pass
  elif isinstance(x, str):
      x = int(x)
  elif isinstance(x, (float, Decimal)):
      x = round(x)
  else:
      raise TypeError('Unsupported type')
  </code></pre>
  <p>How do you write <a href="https://docs.python.org/3/library/functions.html#isinstance" rel="nofollow noreferrer"><code>isinstance</code></a> checks with pattern matching, and how do you test against multiple possible types like <code>(float, Decimal)</code> at the same time?</p>