code: def _macro_defn_action(_s, _l, tokens):
      """
      Builds a dictionary structure which defines the given macro.
      """
      assert len(tokens) == 3
      assert tokens[0] == "@"
      return {tokens[1]: tokens[2]}
  
imports: import functools
  import re
  import nltk.tree
label_desc: Use image node_id 24 for calling a global function with example usage: _macro_defn_action(_s, _l, tokens) and returns: dict