appengine base64 encoded string is different from my local machine's

This is the code:

>>> import base64
>>> id = 1
>>> key = 开发者_高级运维"secret key very long"
>>> enc = base64.urlsafe_b64encode(str(id)+key)
>>> enc
'MXNlY3JldCBrZXkgdmVyeSBsb25n'
>>> base64.urlsafe_b64decode(enc)
'1secret key very long'

Works as intended on my machine, but when I upload this code to google appengine, both encoded and decoded strings are totally different. How come?

EDIT 1: this is the actual code:

import base64
id = 18005
key = "r-$b*8hglm+858&9t043hlm6-&6-3d3vfc4((7yd0dbrakhvi"
enc = base64.urlsafe_b64encode(str(id)+key)
print enc
# local machine: MTgwMDVyLSRiKjhoZ2xtKzg1OCY5dDA0M2hsbTYtJjYtM2QzdmZjNCgoN3lkMGRicmFraHZp
# appengine: PXItJGIqOGhnbG0rODU4Jjl0MDQzaGxtNi0mNi0zZDN2ZmM0KCg3eWQwZGJyYWtodmkxODAwNQ==

I can't explain why per se, but decoding the string you got from appengine shows it prepended an '=' to your key; and appended, rather than prepended, the ID.

>>> key='r-$b*8hglm+858&9t043hlm6-&6-3d3vfc4((7yd0dbrakhvi'
>>> base64.urlsafe_b64decode('PXItJGIqOGhnbG0rODU4Jjl0MDQzaGxtNi0mNi0zZDN2ZmM0KCg3eWQwZGJyYWtodmkxODAwNQ==')
'=r-$b*8hglm+858&9t043hlm6-&6-3d3vfc4((7yd0dbrakhvi18005'
>>> '=' + key + str(18005) == _
True

are you absolutely sure you used the same code on the server?