title: Pandas converting String object to lower case and checking for string
body: <p>I have the below code</p>
  
  <pre><code>import pandas as pd
  private = pd.read_excel("file.xlsx","Pri")
  public = pd.read_excel("file.xlsx","Pub")
  private["ISH"] = private.HolidayName.str.lower().contains("holiday|recess")
  public["ISH"] = public.HolidayName.str.lower().contains("holiday|recess")
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>AttributeError: 'Series' object has no attribute 'contains'
  </code></pre>
  
  <p>Is there anyway to convert the 'HolidayName' column to lower case and then check the regular expression <code>("Holiday|Recess")</code>using <code>.contains</code> in one step?</p>