code: def column_count(self, ):
          
          if self.child_count():
              return self.childItems[0]._data.column_count()
          else:
              return self._data.column_count() if self._data else 0
docs: Return the number of columns that the children have
  
          If there are no children, return the column count of its own data.
  
          :returns: the column count of the children data
          :rtype: int
          :raises: None