Canonicalizing Unbounded Intervals

[vansivallab]

Canonicalizing an unbounded interval changes the meaning of the interval.

As an example:

>>> a = IntInterval((None, None))
>>> infinity.inf in a
False
>>> b = canonicalize(a, lower_inc=True, upper_inc=True)
>>> b
IntInterval('[,]')
>>> infinity.inf in b
True

The initial version (a) of the interval suggests that infinity is not included in the interval, but after the canonicalization infinity is in the interval.