code: def button_clicked(self, button):
          
          if button is self.idx_ok:
  
              #new_format = self.new_format.get_value().lower()
              new_format = 'edf'
              chan = None
              beg = None
              end = None
  
              if not self.all_time.get_value():
                  beg = self.times['beg'].get_value()
                  end = self.times['end'].get_value()
  
              if not self.all_chan.get_value():
                  chan = self.get_channels()
  
              self.parent.info.export(new_format, filename=self.filename,
                                      chan=chan, begtime=beg, endtime=end)
  
              self.accept()
  
          if button is self.idx_cancel:
              self.reject()
docs: Action when button was clicked.
  
          Parameters
          ----------
          button : instance of QPushButton
              which button was pressed