Dedalus plume with t dependent BC error

➜  Plume  python3 plume.py
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2015-02-28 12:44:28,997 __main__ 0/1 INFO :: Solver built
2015-02-28 12:44:29,002 __main__ 0/1 INFO :: Initialization time: 2.247789
2015-02-28 12:44:29,002 __main__ 0/1 INFO :: Starting loop
2015-02-28 12:44:29,011 __main__ 0/1 ERROR :: Exception raised, triggering end of main loop.
2015-02-28 12:44:29,012 __main__ 0/1 INFO :: Iterations: 0
2015-02-28 12:44:29,012 __main__ 0/1 INFO :: Sim end time: 0.000000
2015-02-28 12:44:29,012 __main__ 0/1 INFO :: Run time: 0.01 sec
2015-02-28 12:44:29,012 __main__ 0/1 INFO :: Run time: 0.000003 cpu-hr
Traceback (most recent call last):
  File "/Users/Drummond/dedalus/dedalus/core/field.py", line 36, in __getattr__
    ufunc = UnaryGridFunction.supported[attr]
KeyError: 'data'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "plume.py", line 112, in <module>
    solver.step(dt)
  File "/Users/Drummond/dedalus/dedalus/core/solvers.py", line 339, in step
    self.timestepper.step(self, dt, wall_time)
  File "/Users/Drummond/dedalus/dedalus/core/timesteppers.py", line 525, in step
    evaluator.evaluate_scheduled(wall_time, solver.sim_time, iteration)
  File "/Users/Drummond/dedalus/dedalus/core/evaluator.py", line 97, in evaluate_scheduled
    self.evaluate_handlers(scheduled_handlers, wall_time, sim_time, iteration)
  File "/Users/Drummond/dedalus/dedalus/core/evaluator.py", line 107, in evaluate_handlers
    tasks = self.attempt_tasks(tasks, id=sim_time)
  File "/Users/Drummond/dedalus/dedalus/core/evaluator.py", line 157, in attempt_tasks
    output = task['operator'].attempt(**kw)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 171, in attempt
    return self.evaluate(id=id, force=False)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 124, in evaluate
    a_eval = a.evaluate(id=id, force=force)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 124, in evaluate
    a_eval = a.evaluate(id=id, force=force)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 124, in evaluate
    a_eval = a.evaluate(id=id, force=force)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 124, in evaluate
    a_eval = a.evaluate(id=id, force=force)
  File "/Users/Drummond/dedalus/dedalus/core/future.py", line 157, in evaluate
    self.operate(out)
  File "/Users/Drummond/dedalus/dedalus/core/operators.py", line 305, in operate
    return self.func(self.args[0].value, out=out.data)
  File "/Users/Drummond/dedalus/dedalus/core/field.py", line 39, in __getattr__
    raise AttributeError("%r object has no attribute %r" %(self.__class__.__name__, attr))
AttributeError: 'Scalar' object has no attribute 'data'