TypeError: ListControl, must set a sequence (python error)

Question

I am using Python Mechanize to open a website, fill out a form, and submit that form. It's actually pretty simple. It works until I come across radio buttons and "select" input boxes.

br.open(url)
br.select_form(name="postmsg")
br.form['subject'] = "Is this good for the holidays? "
br.form['message'] = "I'm new to technology."
br.form['E'] = '0'
br.submit()

  br.form['E'] = '0'
  File "build/bdist.linux-x86_64/egg/ClientForm.py", line 2897, in __setitem__
  File "build/bdist.linux-x86_64/egg/ClientForm.py", line 2092, in __setattr__
  File "build/bdist.linux-x86_64/egg/ClientForm.py", line 2100, in _set_value
TypeError: ListControl, must set a sequence

Why am I getting this error? Why can't I set E just like the text boxes? (E is a radio button)

Edit: This is the form, according to Web Developer.

Elements
Index   Id  Name    Type    Value   Label   Size    Maximum Length  State
0   subject subject text            35      
2   message message textarea                    
3   identity    identity    select          1       
13      action_btn  hidden                  
14      _charset_   hidden                  
16      r   hidden  /Stocks_(A_to_Z)/Stocks_G               
9       E   radio   0               

Checked
8       E   radio   1               
15      .crumb  hidden  1n1Yo3MQae3             
7       E   radio   2               
17      bn  hidden  25263               
6       E   radio   3               
5       E   radio   4               
4       E   radio   5               
12  SubmitCancel    SubmitCancel    submit  Cancel              
1   mbpostthreads   threads button  Check Existing Topics First             
11  SubmitPost  SubmitPost  submit  Post Message                
10  SubmitPreview   SubmitPreview   submit  Preview Message             
18  yIdCoreIdUser       hidden  annamae41g  

Answer 1

Radio buttons and Check-boxes can have different behavior then other elements. It depends on their name and id.

If the items have the same name, try doing this:

br.find_control(name="E").value = ["0"]

Another option is:

form.find_control(name="E", kind="list").value = ["0"]

and finally, this might work:

    br["E"] = ["0"]

(I haven't used mechanize in a while so i don't remember exactly).