title: Write a function remove_duplicates in python
body: <p>Write a function called remove_duplicates which will take one argument called string. This string input will only have characters between a-z.</p>
  
  <p>The function should remove all repeated characters in the string and return a tuple with two values:</p>
  
  <p>A new string with only unique, sorted characters.</p>
  
  <p>The total number of duplicates dropped.</p>
  
  <p>For example:</p>
  
  <pre><code>remove_duplicates('aaabbbac') =&gt; ('abc', 5)
  
  remove_duplicates('a') =&gt; ('a', 0)
  
  remove_duplicates('thelexash') =&gt; ('aehlstx', 2)
  </code></pre>
  
  <p>Here's my solution, and I'm new to python:</p>
  
  <pre><code>string = raw_input("Please enter a string...")
  
  def remove_duplicates(string):
    string = set(string)
    if only_letters(string):
      return (string, string.length)
    else:
      print "Please provide only alphabets"
  
  remove_duplicates(string)
  </code></pre>
  
  <p>What might I be doing wrongly? This is the error I get below</p>
  
  <p>THERE IS AN ERROR/BUG IN YOUR CODE
  Results: 
  /bin/sh: 1: python/nose2/bin/nose2: not found</p>
  
  <p>Thanks.</p>