code: def parse_unicode_values_(self):
      location = self.cur_token_location_
      try:
          unicode_values = self.expect_string_().split(",")
          unicode_values = [
              int(uni[2:], 16) for uni in unicode_values if uni != ""
          ]
      except ValueError as err:
          raise VoltLibError(str(err), location)
      return unicode_values if unicode_values != [] else None
  
imports: import fontTools.voltLib.ast
  from fontTools.voltLib.lexer import Lexer
  from fontTools.voltLib.error import VoltLibError
  from io import open
label_desc: Use image node_id 20 for calling the Parser obj's underlying member method code with example usage: obj.parse_unicode_values_() and returns: unknown