concatenate this to another :class:`DeconStim` of the same "type"

def concat_stim(self,decon_stim):
        '''concatenate this to another :class:`DeconStim` of the same "type"'''
        if self.type()!=decon_stim.type():
            nl.notify('Error: Trying to concatenate stimuli of different types! %s (%s) with %s (%s)' % (self.name,self.type(),decon_stim.name,decon_stim.type()),level=nl.level.error)
            return None
        concat_stim = copy.copy(self)
        if self.name=='Blank':
            concat_stim = copy.copy(decon_stim)

        self.read_file()
        if self.type()=="column":
            # if an explicit # of reps is given, concat to that
            reps = [x.reps if x.reps else len(x.column) for x in [self,decon_stim]]
            concat_stim.column = self.column[:reps[0]] + decon_stim.column[:reps[1]]
            return concat_stim
        if self.type()=="times":
            if len(self.times)==0 or '__iter__' not in dir(self.times[0]):
                self.times = [self.times]
            if len(decon_stim.times)==0 or '__iter__' not in dir(decon_stim.times[0]):
                decon_stim.times = [decon_stim.times]
            concat_stim.times = self.times + decon_stim.times
            return concat_stim
        return None