bug in assume()?

[Stan Schymanski]

Dear all, this seems like a bug to me:

----------------------------------------------------------------------
| Sage Version 4.0.2, Release Date: 2009-06-18 |
| Type notebook() for the GUI, and license() for information. |
----------------------------------------------------------------------
sage: var('mvg nvg')
(mvg, nvg)
sage: assume(mvg, 'integer')
sage: assume(nvg, 'integer')
---------------------------------------------------------------------------
AttributeError Traceback (most recent call
last)

/Users/sschym/<ipython console> in <module>()

/Users/sschym/Programs/sage/local/lib/python2.5/site-packages/sage/
symbolic/assumptions.pyc in assume(*args)
194 else:
195 try:
--> 196 x.assume()
197 except KeyError:
198 raise TypeError, "assume not defined for
objects of type '%s'"%type(x)

/Users/sschym/Programs/sage/local/lib/python2.5/site-packages/sage/
symbolic/assumptions.pyc in assume(self)
96 maxima.set("context", cur)
97
---> 98 if not self in _assumptions:
99 maxima.activate(self._context)
100 _assumptions.append(self)

/Users/sschym/Programs/sage/local/lib/python2.5/site-packages/sage/
symbolic/assumptions.pyc in __cmp__(self, other)
70 if isinstance(self, GenericDeclaration) and isinstance
(other, GenericDeclaration):
71 return cmp( (self._var, self._assumption),
---> 72 (other._var, other._assumption) )
73 else:
74 return cmp(type(self), type(other))

/Users/sschym/Programs/sage/local/lib/python2.5/site-packages/sage/
symbolic/expression.so in
sage.symbolic.expression.Expression.__nonzero__ (sage/symbolic/
expression.cpp:7506)()

sage: assumptions()
[mvg is integer]

Why did it work for mvg but not for nvg? This was not a problem in
Sage 3.x.

Cheers,
Stan