title: Glom handling or skipping a PathError for data with different keys?
body: <p>I am using the glom package to help with traversing a big dictionary.</p>
  
  <p>Given this data:</p>
  
  <pre><code>data = {
      'groups': [
          {'instance': {'name': 'football'}},
          {'instance': {'name': 'rugby'}},
          {'id': 145, 'type': 'unknown'},
      ]
  }
  </code></pre>
  
  <p>And using glom, I attempt to get the instance names:</p>
  
  <pre><code>import glom
  instance_names = glom(data, ('groups', ['instance.name']))
  </code></pre>
  
  <p>I receive an Error:</p>
  
  <pre><code>glom.core.PathAccessError: could not access 'instance', part 0 of Path('instance', 'name'), got error: KeyError('instance')
  </code></pre>
  
  <p>How can I skip the objects where the <code>instance</code> key does not exist?</p>
  
  <p><strong>Update</strong></p>
  
  <p>I have tried to skip the exception but then I receive empty results:</p>
  
  <pre><code>instance_names = glom(data, ('groups', ['instance.name']), skip_exc=PathAccessError)
  </code></pre>