Goal:
    z : Z
  ============================
   (True -> False -> None = Some z)


DEBUG:Going to execute:
symmetry; trivial
Level 1: Backtrace:

In environment
z : Z
H : True
H0 : False
Unable to unify "Some z" with "None".
Level 0: Backtrace:

In environment
z : Z
H : True
H0 : False
Unable to unify "Some z" with "None".