Merge pull request statsmodels#6118 from khs/patch-3

Update summary2.py

Author: bashtage

statsmodels/iolib/summary2.py

@@ -469,9 +469,9 @@ def summary_col(results, float_format='%.4f', model_names=(), stars=False,
         dict of functions to be applied to results instances to retrieve
         model info. To use specific information for different models, add a
         (nested) info_dict with model name as the key.
-        Example: `info_dict = {"N":..., "R2": ..., "OLS":{"R2":...}}` would
-        only show `R2` for OLS regression models, but additionally `N` for
-        all other results.
+        Example: `info_dict = {"N":lambda x:(x.nobs), "R2": ..., "OLS":{
+        "R2":...}}` would only show `R2` for OLS regression models, but
+        additionally `N` for all other results.
         Default : None (use the info_dict specified in
         result.default_model_infos, if this property exists)
     regressor_order : list[str], optional