def trim_left_of_sel(self, *args):
        if len(self.selection) > 0:
            first_sel_index = min([sel.index for sel in self.selection])
            self.data = self.data[first_sel_index:]
Return a periodic square-wave waveform.
dataset/ETHPy150Open kivy/kivy/kivy/adapters/listadapter.py/ListAdapter.trim_left_of_sel--crossover with--dataset/ETHPy150Open scipy/scipy/scipy/signal/waveforms.py/square