code: def expect_number_(self):
      self.advance_lexer_()
      if self.cur_token_type_ is not Lexer.NUMBER:
          raise VoltLibError(
              "Expected a number", self.cur_token_location_
          )
      return self.cur_token_
  
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 32 for calling the Parser obj's underlying member method code with example usage: obj.expect_number_() and returns: self