There is no applicable method for the generic function
  #<STANDARD-GENERIC-FUNCTION NET.ACCELERATION.CHARTING::DRAW-ZERO-P (1)>
when called with arguments
  (NIL).
   [Condition of type SIMPLE-ERROR]

Restarts:
 0: [RETRY] Retry calling the generic function.
 1: [RETRY] Retry SLIME REPL evaluation request.
 2: [*ABORT] Return to SLIME's top level.
 3: [ABORT] abort thread (#<THREAD "new-repl-thread" RUNNING {1001EECEA3}>)

Backtrace:
  0: ((:METHOD NO-APPLICABLE-METHOD (T)) #<STANDARD-GENERIC-FUNCTION NET.ACCELERATION.CHARTING::DRAW-ZERO-P (1)> NIL) [fast-method]
  1: (SB-PCL::CALL-NO-APPLICABLE-METHOD #<STANDARD-GENERIC-FUNCTION NET.ACCELERATION.CHARTING::DRAW-ZERO-P (1)> (NIL))
  2: ((:METHOD NET.ACCELERATION.CHARTING::CALCULATE-GRAPH-BOUNDS (NET.ACCELERATION.CHARTING::LINE-CHART T)) #<NET.ACCELERATION.CHARTING::LINE-CHART {10021D0DE3}> #<NET.ACCELERATION.CHARTING::GRAPH-REGION {..
  3: ((:METHOD NET.ACCELERATION.CHARTING::DRAW-CHART (NET.ACCELERATION.CHARTING::LINE-CHART)) #<NET.ACCELERATION.CHARTING::LINE-CHART {10021D0DE3}>) [fast-method]
  4: (NET.ACCELERATION.CHARTING::%RENDER-CHART #<NET.ACCELERATION.CHARTING::LINE-CHART {10021D0DE3}>)
  5: ((:METHOD NET.ACCELERATION.CHARTING::SAVE-CHART-TO-FILE (T NET.ACCELERATION.CHARTING::CHART)) "minimal-line-chart.png" #<NET.ACCELERATION.CHARTING::LINE-CHART {10021D0DE3}>) [fast-method]
  6: ((LAMBDA ()))
  7: (SB-INT:SIMPLE-EVAL-IN-LEXENV (NET.ACCELERATION.CHARTING:WITH-LINE-CHART (400 300) (NET.ACCELERATION.CHARTING:ADD-SERIES "A" (QUOTE #)) (NET.ACCELERATION.CHARTING:ADD-SERIES "B" (QUOTE #)) (NET.ACCELE..
  8: (EVAL (NET.ACCELERATION.CHARTING:WITH-LINE-CHART (400 300) (NET.ACCELERATION.CHARTING:ADD-SERIES "A" (QUOTE #)) (NET.ACCELERATION.CHARTING:ADD-SERIES "B" (QUOTE #)) (NET.ACCELERATION.CHARTING:SAVE-FIL..
 --more--