Problem with subprocess.Popen wget within a thread

Hi

it seems the script (A) finishes before the downloading ends, and the
(B) version doesn't (wanted behavior) ... this is unexpected. What
happens ?
(A) ============================================
class vid(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def download(self):
self.cmd = 'wget
ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/7.0/7.0-RELEASE-i386-bootonly.iso'
self.child = subprocess.Popen(self.cmd.split())
def run(self):
self.download()

def main():
w = vid()
w.start()
w.join()

(B) ============================================
class vid(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def download(self):
self.cmd = 'wget
ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/7.0/7.0-RELEASE-i386-bootonly.iso'
self.child = subprocess.Popen(self.cmd.split(), stderr=subprocess.PIPE)
def run(self):
self.download()
self.child.stderr.readlines()

def main():
w = vid()
w.start()
w.join()
============================================