title: xlwings udf function erase next cell on excel
body: <p>I have a little problem on excel using xlwings and i really don't know how to fix it. 
  When i'm using an UDF function that return for example a panda dataframe, let suppose that my dataframe is 3 colums width (no necessary condition on rows), then on the 4th columns in excel, if i write some datas on it, my panda dataframe will erase it as soon as i calculate the sheet... Although the dataframe is not using this column at all while it's 3 columns large and not 4 ...
  I don't know if i'm clear enough. Let me know !</p>
  
  <p>thank you very much in advance.</p>
  
  <pre><code>@xw.func
  @xw.ret(expand='table') 
  def hello(nb):
      nb = int(nb)
      return [["hello","you"] for i in range(nb)]
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/cdEQ8.png" rel="nofollow noreferrer">before recalculate the sheet</a></p>
  
  <p><a href="https://i.stack.imgur.com/Qu7ow.png" rel="nofollow noreferrer">after recalculate the sheet</a></p>