How do I scrape nested data using selenium and Python>

I basically want to scrape the date under <span class="visually-hidden">, but I can't see to get to it. Here's the HTML at code:

<div class="pv-entity__summary-info">

<h3 class="Sans-17px-black-85%-semibold">Litigation Paralegal</h3>

<h4>
  <span class="visually-hidden">Company Name</span>
  <span class="pv-entity__secondary-title Sans-15px-black-55%">Olswang</span>
</h4>


  <div class="pv-entity__position-info detail-facet m0"><h4 class="pv-entity__date-range Sans-15px-black-55%">
      <span class="visually-hidden">Dates Employed</span>
      <span>Feb 2016 – Present</span>
    </h4><h4 class="pv-entity__duration de Sans-15px-black-55% ml0">
        <span class="visually-hidden">Employment Duration</span>
        <span class="pv-entity__bullet-item">1 yr 2 mos</span>
      </h4><h4 class="pv-entity__location detail-facet Sans-15px-black-55% inline-block">
      <span class="visually-hidden">Location</span>
      <span class="pv-entity__bullet-item">London, United Kingdom</span>
    </h4></div>

</div>

And here is what I've been doing at the moment with selenium in my code:

        date= browser.find_element_by_xpath('.//div[@class = "pv-entity__duration de Sans-15px-black-55% ml0"]').text
        print date

But this gives no results. How would I go about either pulling the date?