code: def userdesc_parse(env, sig, signode):
      x, y = sig.split(":")
      signode += addnodes.desc_name(x, x)
      signode += addnodes.desc_parameterlist()
      signode[-1] += addnodes.desc_parameter(y, y)
      return x
  
file_path: sphinx/tests/roots/test-root/conf.py
imports: import os
  import sys
  from docutils import nodes
  from docutils.parsers.rst import Directive
  from sphinx import addnodes
label_desc: Use image node_id 1 for calling a global function with example usage: userdesc_parse(env, sig, signode) and returns: x