returns the Inter Spike Intervals

                `time_dimension`: which dimension contains the spike times (by default the first)

                `units`,`min_t`,`max_t`: define the units of the output and the range of spikes that should be considered

def ISIs(self,time_dimension=0,units=None,min_t=None,max_t=None):
        """
            returns the Inter Spike Intervals

                `time_dimension`: which dimension contains the spike times (by default the first)

                `units`,`min_t`,`max_t`: define the units of the output and the range of spikes that should be considered
        """
        units = self._default_units(units)
        converted_dimension,st = self.spike_times.get_converted(time_dimension,units)
        if min_t is None:
            min_t = converted_dimension.min
        if max_t is None:
            max_t = converted_dimension.max
        return np.diff(sorted(st[(st>min_t) * (st <max_t)]))