title: Remove empty rows from dataframe in the python function
body: <p>I want to find specific rows in a huge dataframe and assign a comment if the condition is met.</p>
  
  <p>The part of the code I use is as follows:</p>
  
  <pre><code>def check_car(x):
          if x['CAR'] == 'FERRARI' and x['COUNTRY'] != 'ITALY':
              return 'This is wrong'
          else:
              x.drop()
  </code></pre>
  
  <p>After that I use this function to create new data frame with ID and comment.
  The new data frame contain IDs with <code>“This is wrong”</code> as well as <code>None</code> values.
  Instead of that I want to remove all None values from data frame, is it possible to do that in the function itself?</p>
  
  <p>I used <code>x.drop</code> but I got the error:</p>
  
  <pre><code>ValueError: ("Need to specify at least one of 'labels', 'index' or 'columns'”)
  </code></pre>