title: Unescaped left brace in regex is deprecated, passed through in regex;
body: <p>I am trying to write a program to find the sum of a list using recursion in python and my code is this  </p>
  
  <pre><code>value = 0
  
  def sum_list(alist):
      global value
      if len(alist) == 0:
          return value
      value += alist.pop()
      return sum_list(alist)
  
  print sum_list(range(10))
  </code></pre>
  
  <p>But when i am executing this script I am getting a weired error.  </p>
  
  <pre><code>Unescaped left brace in regex is deprecated, passed through in regex; marked by &lt;-- HERE in m/%{ &lt;-- HERE (.*?)}/ at /usr/bin/print line 528.
  Error: no "print" mailcap rules found for type "text/x-python"
  </code></pre>
  
  <p>I searched for it but couldn't get why this error is coming.
  Help will be appreciated</p>