title: Filter a dictionary based on the value of its date keys
body: <p>I want to import articles from as many sources around the world as from a certain date.</p>
  
  <pre><code>import requests
  url = ('https://newsapi.org/v2/top-headlines?'
         'country=us&amp;'
         'apiKey=de9e19b7547e44c4983ad761c104278f')
  response = requests.get(url)
  
  response_dataframe = pd.DataFrame(response.json())
  
  articles = {article for article in response_dataframe['articles'] if article['publishedAt'] &gt;= '2019-01-04T11:30:00Z'}
  print(articles)
  </code></pre>
  
  <p>But I get:</p>
  
  <pre><code>---------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-84-0f21f2f50907&gt; in &lt;module&gt;
        2 response_dataframe['articles'][1]['publishedAt']
        3 
  ----&gt; 4 articles = {article for article in response_dataframe['articles'] if article['publishedAt'] &gt;= '2018-01-04T11:30:00Z'}
        5 print(articles)
  
  &lt;ipython-input-84-0f21f2f50907&gt; in &lt;setcomp&gt;(.0)
        2 response_dataframe['articles'][1]['publishedAt']
        3 
  ----&gt; 4 articles = {article for article in response_dataframe['articles'] if article['publishedAt'] &gt;= '2018-01-04T11:30:00Z'}
        5 print(articles)
  
  TypeError: unhashable type: 'dict'
  </code></pre>
  
  <p>Therefore how to select a range of articles according by selecting on these keys ?
  The expected output is a dataframe sorting the articles by the day and the newspaper.</p>
  
  <pre><code>              The New York Times                                The Washington Post                                The Financial Times  
  2007-01-01    . What Sticks from '06. Somalia Orders Islamis... New Ebola Vaccine Gives 100 Percent Protecti...
  2007-01-02    . Heart Health: Vitamin Does Not Prevent Death... Flurry of Settlements Over Toxic Mortgages M...
  2007-01-03    . Google Answer to Filling Jobs Is an Algorith... Jason Miller Backs Out of White House Commun...
  2007-01-04    . Helping Make the Shift From Combat to Commer... Wielding Claims of ‘Fake News,’ Conservative...
  2007-01-05    . Rise in Ethanol Raises Concerns About Corn a... When One Party Has the Governor’s Mansion an
  ...
  </code></pre>
  
  <p>My Python version is 3.6.6</p>