code: def _get_to_one_relationship_value(self, obj, column):
          
          related_key = column.get('related_key', None)
          related = getattr(obj, column['__col__'].key)
          if related:
              if related_key is not None:
                  value = self._get_formatted_val(
                      related, related_key, column
                  )
              else:
                  value = column['__prop__'].compile_obj(related)
          else:
              value = ""
          return value
docs: Compute datas produced for a many to one relationship
  
          :param obj obj: The instance we manage
          :param dict column: The column description dictionnary
          :returns: The associated value