code: def sequence(self):
          '''
          sort the points in the line with given option
          '''
          if (len(self.Points[0]) == 2):
              if (self.Sort == 'X' or self.Sort == 'x'):
                  self.Points.sort(key=lambda x: x[0])
                  self.order(self.Points)
              elif (self.Sort == 'Y' or self.Sort == 'y'):
                  self.Points.sort(key=lambda x: x[1])
                  self.order(self.Points)
              else:
                  self.order(self.Points)
          if (len(self.Points[0]) == 3):
              if (self.Sort == 'X' or self.Sort == 'x'):
                  self.Points.sort(key=lambda x: x[0])
                  self.order(self.Points)
              elif (self.Sort == 'Y' or self.Sort == 'y'):
                  self.Points.sort(key=lambda x: x[1])
                  self.order(self.Points)
              elif (self.Sort == 'Z' or self.Sort == 'Z'):
                  self.Points.sort(key=lambda x: x[2])
                  self.order(self.Points)
              else:
                  self.order(self.Points)