class_docstr: An expression for generating arrays by summing different columns from
  a ``ColumnDataSource``.
  
  This expression is useful for implementing stacked bar charts at a low
  level.
class_docstr_tok: ["An","expression","for","generating","arrays","by","summing","different","columns","from","a","``","ColumnDataSource","``",".","This","expression","is","useful","for","implementing","stacked","bar","charts","at","a","low","level","."]
code: def __init__(self, *args, **kwargs) -> None:
      super().__init__(*args, **kwargs)
  
imports: from __future__ import annotations
  import logging
  from math import inf
  from ..core.enums import Direction
  from ..core.has_props import abstract
  from ..core.properties import AngleSpec, AnyRef, Bool, Dict, Enum, Float, Instance, Nullable, NumberSpec, Required, Seq, String, field
  from ..model import Model
label_desc: Use image node_id 1 to create a new Stack object from inherited base classes: Expression with example: obj = Stack()