code: def _iris_obj_to_attrs(obj):
      
      attrs = {'standard_name': obj.standard_name,
               'long_name': obj.long_name}
      if obj.units.calendar:
          attrs['calendar'] = obj.units.calendar
      if obj.units.origin != '1' and not obj.units.is_unknown():
          attrs['units'] = obj.units.origin
      attrs.update(obj.attributes)
      return dict((k, v) for k, v in attrs.items() if v is not None)
docs: Return a dictionary of attrs when given a Iris object