title: to_csv, Where am I wrong
body: <p>I have this code</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  import csv
  
  odata = pd.read_csv('email.csv')
  data = odata.drop('content', axis=1, inplace=True)
  data.to_csv('email-out.csv', index=False, sep=',')
  </code></pre>
  
  <p>And I got error like that:</p>
  
  <pre><code>Traceback (most recent call last):
    File "cut.py", line 7, in &lt;module&gt;
      data.to_csv('email-out.csv', index=False, sep=',')
  AttributeError: 'NoneType' object has no attribute 'to_csv'
  </code></pre>
  
  <p>Where am I wrong?
  help me..please</p>