code: def merge_xrefs(app, env, docnames, other):
      if not hasattr(env, "all_sampledata_xrefs"):
          env.all_sampledata_xrefs = []
  
      if hasattr(other, "all_sampledata_xrefs"):
          env.all_sampledata_xrefs.extend(other.all_sampledata_xrefs)
  
imports: from __future__ import annotations
  from sphinx.util import logging
  from os.path import basename
  from docutils import nodes
  from sphinx.locale import _
  from .None import PARALLEL_SAFE
  from .bokeh_directive import BokehDirective
  from .util import get_sphinx_resources
label_desc: Use image node_id 3 for calling a global function with example usage: merge_xrefs(app, env, docnames, other) without return types