QGIS » QGIS Application

In the latest master, QGIS creates scratch.py under .qgis2/python/expression folder. The file stops older versions of QGIS start and comes up with the following error:
Couldn't load qgis.user.
Python support will be disabled.


Traceback (most recent call last):
File "", line 1, in
File "C:/OSGEO4~1/apps/qgis/./python\\qgis\\utils.py", line 478, in _import
mod = _builtin_import(name, globals, locals, fromlist, level)
File "C:/OSGEO4~1/apps/qgis/./python\\qgis\\user.py", line 42, in
expressions.load(expressionspath)
File "C:/OSGEO4~1/apps/qgis/./python\\qgis\\user.py", line 19, in load_user_expressions
__import__("expressions.{0}".format(name), locals(), globals())
File "C:/OSGEO4~1/apps/qgis/./python\\qgis\\utils.py", line 478, in _import
mod = _builtin_import(name, globals, locals, fromlist, level)
File "C:/Users/Saber/.qgis2/python\\expressions\\scratch.py", line 9, in
@qgsfunction(group='Custom')
TypeError: qgsfunction() takes exactly 2 arguments (1 given)

To reproduce the error:
1- Open QGIS master
2- Add a vector file
3- Use vector calculator to add a column
4- Save your layer
5- Exit QGIS master
6- Try to open QGIS 2.8.2