code: def _get_node_column(cls, node, column_name):
          
          if not hasattr(node, 'columns'):
              node.set('columns', {})
  
          if column_name in node.columns:
              column = node.columns[column_name]
          else:
              column = {'name': column_name, 'description': ''}
              node.columns[column_name] = column
  
          return column
docs: Given a ParsedNode, add some fields that might be missing. Return a
          reference to the dict that refers to the given column, creating it if
          it doesn't yet exist.