code: def setup(app):
      lexers["peg"] = PEGLexer()
      return {"version": "1.0", "parallel_read_safe": True}
  
imports: from pygments.lexer import RegexLexer, bygroups, include
  from pygments.token import Comment, Keyword, Name, Operator, Punctuation, Text
  from sphinx.highlighting import lexers
label_desc: Use image node_id 1 for calling a global function with example usage: setup(app) and returns: dict