code: def asDictionary(self):
          
          template = {
              "xmin" : self._xmin,
              "ymin" : self._ymin,
              "xmax" : self._xmax,
              "ymax" : self._ymax,
              "spatialReference" : self.spatialReference
          }
          if self._zmax is not None and \
             self._zmin is not None:
              template['zmin'] = self._zmin
              template['zmax'] = self._zmax
  
          if self._mmin is not None and \
             self._mmax is not None:
              template['mmax'] = self._mmax
              template['mmin'] = self._mmin
  
          return template
docs: returns the envelope as a dictionary