title: How to obtain first date of each month based on given year range in Nifi flow
body: <p>I would like to know what could be the best way to obtain the starting date values for each month based on the date range.</p>
  
  <p>For example: If I am given a year range of <code>2015-11-10 and 2018-01-15</code>(format YYYY-mm-dd). Then I would like to extract following dates: </p>
  
  <pre><code>2015-12-01
  2016-01-01
  .
  .
  2018-01-01
  </code></pre>