Python3 urllib.request fetching partial xml data from the Quickbuild Api

Question

I am using default urllib module of python 3.7.

By using this I am calling an Quickbuild 12 api

http://localhost:8810/rest/builds/<build id>

to get the builds data. but I am getting partial result from this.

Example

expected:

<?xml version="1.0" encoding="UTF-8"?>
<x>somthing<\x>
<A>
    <B>somthing<\B>
<\A>

Getting

<?xml version="1.0" encoding="UTF-8"?>
<x>somthing<\x> 
<\A>

sample code:

def get_data(build_id):
    password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()
    top_level_url = "http://localhost:8810"
    password_mgr.add_password(None, top_level_url, QBUSERNAME, QBPASSWORD)
    handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
    opener = urllib.request.build_opener(handler)
    urllib.request.install_opener(opener)
    URL = "http://localhost:8810/rest/builds/%d" % build_id
    y = opener.open(URL)
    print (y.read())

Please help me in identifying what is causing this issue. and what can I do to get full data.