converting JSON to string

[Gowri]

Hello,

I actually have two questions:
1. Are there any libraries which convert XML to JSON?
2. I am currently doing the above using the DOM parser and creating a
JSON array

<snippet>
for node in doc.getElementsByTagName("book"):
                isbn = node.getAttribute("isbn")
                titleNode = (node.getElementsByTagName("title")
[0]).childNodes[0]
                title = titleNode.data
                primarykeys.append({'isbn': isbn, 'title': title})
return primarykeys

I want to send primarykeys as a response to my client. i use
mod_python and apache. The problem is, I have not been able to figure
out how to convert my JSON output to a string.

Could someone please help me?

Thanks in advance