#7805

Fixed the bug by returning False when the method _contains of an Interval gets another Interval
On Mon, Aug 04, 2014 at 02:45:50AM -0700, Samuel Lê wrote:
>    Well, sometimes you can't evaluate that function with symbolic inputs:
>    In [6]: from sympy import Symbol, Interval
>    In [7]: x = Symbol('x')
>    In [8]: interval = Interval(0,1)
>    In [9]: x in interval
>    TypeError: proposition must be a valid logical expression
> 
>    Should I leave it as it is?

Yes.  Please, try to understand the code first.  Why there is the
contains method, why the __contains__...

>    concerning the case of isinstance, would this line cover all the cases we
>    want to avoid?
>    if isinstance(other, Set):
>    return False

For the Interval class - maybe.  But the problem seems to be
much more generic.