Optstrategy and skipped combinations

Hello
I'm newbie about this framework, but I'm studing it with a lot of interest.
I'm trying to do optimization of two or more parametersp1 = range(2, 8) #(2, 3, 4)
p2 = range(9, 10) #(10, 12, 14)
p3 = 2#range(2, 6) # (2, 3, 4)
cerebro.optstrategy(StrategyIm, ema1period=p1, ema2period=p2, stddevmult=p3)and I noticed that cerebro doen't execute all parameters combinations. I need all results for plotting and doing my analisys outside cerebro.
What I'm doing wrong?
Thankyou for any idea 
A bit more about the problem: Cerebro executes all the combinations. I can find it in the cycle after run:
opt_runs = self.cerebro.run(optreturn=True)
for run in opt_runs:
for strategy in run:
ema1period = strategy.params.ema1period
ema2period = strategy.params.ema2period
takeprofitmult = strategy.params.takeprofitmult
stoplossmult = strategy.params.stoplossmult
print('EMA1 Period' + str(ema1period) + 'EMA2 Period' + str(ema2period) + 'TAKEPROFIT MULT' + str(
takeprofitmult)+ 'stoploss MULT' + str(stoplossmult))The problem is that the stop method of the strategy is not called for every parameter combination..is correct?

I did a workaround about my problem. I was interested in data which I found using analyzers. Of sure the best way to use backtrader!!!