title: Converting dictionary with values in List to Pandas DataFrame
body: <p>I have a dictionary with City names as keys and corresponding to each city there is a list of dates. For Example:</p>
  
  <pre><code>{
  'A':['2017-01-02','2017-01-03'],
  'B':['2017-02-02','2017-02-03','2017-02-04','2017-02-05'],
  'C':['2016-02-02']
  }
  </code></pre>
  
  <p>And I want to convert this to the following dataframe with 2 columns.</p>
  
  <pre><code>City_Name  Date
  A          2017-01-02
  A          2017-01-03
  B          2017-02-02
  B          2017-02-03
  B          2017-02-04
  B          2017-02-05
  C          2016-02-02
  </code></pre>