title: does happybase table.put accept none string value?
body: <p>I have been testing table.put using java and python.</p>
  
  <p>In java, you can write int or float values into a column. using happybase</p>
  
  <pre><code>table.put(line_item_key, {'allinone:quantity': quantity})
  </code></pre>
  
  <p>it bombs out with 
  TypeError: object of type 'int' has no len()</p>
  
  <p>Could this be true that happybase does not support write out anything other than string?</p>