title: Using DATEADD and NOW() together
body: <p>If I try adding the following Measure into my DimDate table:</p>
  
  <pre><code>Past6Months = 
  IF(
      FIRSTDATE(  'Dates'[FullDate] ) &gt;= DATEADD( NOW(), -7, MONTH ),
      TRUE(),
      FALSE()
      )
  </code></pre>
  
  <p>I get this error:</p>
  
  <blockquote>
    <p>The first argument to 'DATEADD' must specify a column.</p>
  </blockquote>