title: Creating text index in pymongo
body: <p>I have a database of English words stored in the field 'h'. I've just found out about text indexes and I wanna create one on this field to speed up searching by regex, but somehow, I just can't get the syntax right. I'm using pymongo 2.7.1 and python 3.4.</p>
  
  <pre><code> from pymongo import MongoClient
   from pymongo import ASCENDING
   from pymongo import DESCENDING
   from pymongo import TEXT
   #...
   collection.create_index('h', TEXT)
  </code></pre>
  
  <p>And I'm getting the following error:</p>
  
  <pre><code>in create_index
  raise TypeError("cache_for must be an integer or float.")
  TypeError: cache_for must be an integer or float.
  </code></pre>
  
  <p>Note that ASCENDING and DESCENDING work. Also I'd like to set the default language as English.</p>