code: def conditional_accept(self):
          
          if self.ui.calfileRadio.isChecked() and str(self.ui.calChoiceCmbbx.currentText()) == '':
              self.ui.noneRadio.setChecked(True)
          if self.ui.calfileRadio.isChecked():
              try:
                  x, freqs = self.datafile.get_calibration(str(self.ui.calChoiceCmbbx.currentText()), self.calf)
              except IOError:
                  QtGui.QMessageBox.warning(self, "File Read Error", "Unable to read calibration file")
                  return
              except KeyError:
                  QtGui.QMessageBox.warning(self, "File Data Error", "Unable to find data in file")
                  return
              if self.ui.frangeLowSpnbx.value()    < freqs[0] or \
                  self.ui.frangeHighSpnbx.value() > freqs[-1]:
                  QtGui.QMessageBox.warning(self, "Invalid Frequency Range", 
                      "Provided frequencys outside of calibration file range of {} - {} Hz".format(freqs[0], freqs[-1]))
                  return
  
          self.accept()
docs: Accepts the inputs if all values are valid and congruent.
          i.e. Valid datafile and frequency range within the given calibration dataset.