core :: Object :: !=
!= is equivalent with not ==.
# Have `self` and `other` different values?
# `!=` is equivalent with `not ==`.
fun !=(other: nullable Object): Bool do return not (self == other)
redef fun !=(b) is intern
redef fun !=(i) is intern
redef fun !=(o) is intern do return not is_same_instance(o)
redef fun !=(o) is intern