title: ValueError: unsupported format character '{' (0x7b) in defining dictionary
body: <p>I'm writing some code for web development using Google Python Appengine. In my code I have to concatenate strings using % and dictionary Here's the code I've written. </p>
  
  <pre><code>def print_form(self, unameError='', passwdError='', verpasswdError='', emailError='', unameValue='', emailValue='' ):
      self.response.out.write( form3 % {  "unameError"    : unameError, 
                                          "passwdError"   : passwdError, 
                                          "verpasswdError": verpasswdError, 
                                          "emailError"    : emailError, 
                                          "unameValue"    : unameValue,  
                                          "emailValue"    : emailValue
                                       }  
                              )
  </code></pre>
  
  <p>For this code, I'm receiving this error from server :</p>
  
  <blockquote>
    <p>web-app-local-directory-path/main.py", line 139, in print_form
        "emailValue"  : emailValue ValueError: unsupported format character '{' (0x7b) at index 218</p>
  </blockquote>
  
  <p>I can't seem to figure out what is wrong in this code. I've defined a valid dictionary and there seem to be no problem with it according to me. </p>
  
  <p>Somebody please help me on this.</p>
  
  <p>Regards
  Vaid, Abhishek</p>