code: def field_cache_to_index_pattern(self, field_cache):
          
          mapping_dict = {}
          mapping_dict['customFormats'] = "{}"
          mapping_dict['title'] = self.index_pattern
          # now post the data into .kibana
          mapping_dict['fields'] = json.dumps(field_cache, separators=(',', ':'))
          # in order to post, we need to create the post string
          mapping_str = json.dumps(mapping_dict, separators=(',', ':'))
          return mapping_str
docs: Return a .kibana index-pattern doc_type