code: def _compute(self):
          
          if self.xvals:
              xmin = min(self.xvals)
              xmax = max(self.xvals)
              xrng = (xmax - xmin)
          else:
              xrng = None
  
          if self.yvals:
              ymin = min(min(self.yvals), self.zero)
              ymax = max(max(self.yvals), self.zero)
              yrng = (ymax - ymin)
          else:
              yrng = None
  
          for serie in self.all_series:
              serie.points = serie.values
  
          if xrng:
              self._box.xmin, self._box.xmax = xmin, xmax
          if yrng:
              self._box.ymin, self._box.ymax = ymin, ymax
  
          if self.range and self.range[0] is not None:
              self._box.ymin = self.range[0]
  
          if self.range and self.range[1] is not None:
              self._box.ymax = self.range[1]
docs: Compute x/y min and max and x/y scale and set labels