code: def to_workspace_value(self, result, assets):
          
          if self.dtype == int64_dtype:
              return super(Classifier, self).to_workspace_value(result, assets)
  
          assert isinstance(result.values, pd.Categorical), (
              'Expected a Categorical, got %r.' % type(result.values)
          )
          with_missing = pd.Series(
              data=pd.Categorical(
                  result.values,
                  result.values.categories.union([self.missing_value]),
              ),
              index=result.index,
          )
          return LabelArray(
              super(Classifier, self).to_workspace_value(
                  with_missing,
                  assets,
              ),
              self.missing_value,
          )
docs: Called with the result of a pipeline. This needs to return an object
          which can be put into the workspace to continue doing computations.
  
          This is the inverse of :func:`~zipline.pipeline.term.Term.postprocess`.