title: Update one dictionary with another in python
body: <p>I am trying to send a dictionary key through command line. <code>sys.argv[1]</code> has the key.
  This key is store in <code>var2</code> and send to <code>append_func</code> which is a another file append.
  dynamically whenever I give command line arguments for key, I want dictionary to get appended. But its overwriting everytime when ever i enter new commandline argument</p>
  
  <p>Please look at the code : </p>
  
  <pre><code>##filename : dictionary.py## 
  
  import sys
  import append
  dic={}
  var1=sys.argv[0]
  var2=sys.argv[1]
  dicto=append.append_fun(var2,dic)
  dic=dic.update(dicto)
  print dic
  
  ##filename : append.py##
  def append_fun(var2,dic1):
      dic1[var2] = "hello"
      return dic1
  </code></pre>
  
  <p>In the command line i am calling <code>dictionary.py test</code>. Again when i call, <code>dictionary.py  test1</code> it does not append <code>dic</code> with both values, it will overwrite with second one. </p>
  
  <p>Please help me how to append <code>dic</code> dictionary</p>