title: How can I import the boto3 ssm ParameterNotFound exception?
body: <p>I would like to <code>import</code> the <code>exception</code> that occurs when a <code>boto3</code> <code>ssm</code> parameter is not found with <code>get_parameter</code>.  I'm trying to add some extra <code>ssm</code> functionality to the <code>moto</code> library, but I am stumped at this point.</p>
  
  <pre><code>&gt;&gt;&gt; import boto3
  &gt;&gt;&gt; ssm = boto3.client('ssm')
  &gt;&gt;&gt; try:
          ssm.get_parameter(Name='not_found')
      except Exception as e:
          print(type(e))
  &lt;class 'botocore.errorfactory.ParameterNotFound'&gt;
  &gt;&gt;&gt; from botocore.errorfactory import ParameterNotFound
  ImportError: cannot import name 'ParameterNotFound'
  &gt;&gt;&gt; import botocore.errorfactory.ParameterNotFound
  ModuleNotFoundError: No module named 'botocore.errorfactory.ParameterNotFound'; 'botocore.errorfactory' is not a package
  </code></pre>
  
  <p>However, the <code>Exception</code> cannot be imported, and does not appear to exist in the botocore code.  How can I import this exception?</p>