text: Title: Can't find "index"
  Body: Hi ! There some trouble in the running process of sweetviz.
  
  My code is `report = sw.analyze(df_a)`
  
  But python noted e with the following keyerror
  `"None of ['index'] are in the columns"`
  
  I had checked my columns' name, and tried to resent the index as well, however, pyhton still send the notes.
  Hope for ur help if it is convenient !
  
  The whole error notes
  `---------------------------------------------------------------------------
  KeyError                                  Traceback (most recent call last)
  Cell In[57], line 1
  ----> 1 report = sw.analyze(df_a)
  
  File ~\AppData\Roaming\Python\Python39\site-packages\sweetviz\sv_public.py:12, in analyze(source, target_feat, feat_cfg, pairwise_analysis)
        8 def analyze(source: Union[pd.DataFrame, Tuple[pd.DataFrame, str]],
        9             target_feat: str = None,
       10             feat_cfg: FeatureConfig = None,
       11             pairwise_analysis: str = 'auto'):
  ---> 12     report = sweetviz.DataframeReport(source, target_feat, None,
       13                                       pairwise_analysis, feat_cfg)
       14     return report
  
  File ~\AppData\Roaming\Python\Python39\site-packages\sweetviz\dataframe_report.py:256, in DataframeReport.__init__(self, source, target_feature_name, compare, pairwise_analysis, fc)
      253 for f in features_to_process:
      254     # start = time.perf_counter()
      255     self.progress_bar.set_description_str(f"Feature: {f.source.name}")
  --> 256     self._features[f.source.name] = sa.analyze_feature_to_dictionary(f)
      257     self.progress_bar.update(1)
      258     # print(f"DONE FEATURE------> {f.source.name}"
      259     #       f" {(time.perf_counter() - start):.2f}   {self._features[f.source.name]['type']}")
      260 # self.progress_bar.set_description_str('[FEATURES DONE]')
      261 # self.progress_bar.close()
      262 
      263 # Wrap up summary
  
  File ~\AppData\Roaming\Python\Python39\site-packages\sweetviz\series_analyzer.py:92, in analyze_feature_to_dictionary(to_process)
       89