code: def setup(app):
      """Required Sphinx extension setup function."""
      app.add_directive_to_domain(
          "py", "bokeh-color", BokehColorDirective
      )
  
      return PARALLEL_SAFE
  
file_path: bokeh/src/bokeh/sphinxext/bokeh_color.py
imports: from __future__ import annotations
  import logging
  from docutils import nodes
  from docutils.parsers.rst.directives import unchanged
  from bokeh.colors import named
  from .None import PARALLEL_SAFE
  from .bokeh_directive import BokehDirective
  from .templates import COLOR_DETAIL
label_desc: Use image node_id 1 for calling a global function with example usage: setup(app) and returns: PARALLEL_SAFE