code: def dicts_to_dict(dictionaries, key_subfieldname):
      
      result = {}
      for d in dictionaries:
          result[d[key_subfieldname]] = d
      return result
docs: Convert a list of dictionaries into a dictionary of dictionaries.
  
      key_subfieldname must exist in each Record's subfields and have a value,
      which will be used as the key for the new dictionary. If a key is duplicated,
      the earlier value will be overwritten.