def diff_except_for_webdriver
      result = compare_commands(@spec_commands, @implemented_core_commands)
      white_list.each { |v| result.delete v }
      result
    end
def diff_except_for_webdriver
      result = compare_commands(@spec_commands, @implemented_core_commands)
      white_list.each { |v| result.delete v }
      result
    end
Commands, only this core library, which haven't been implemented in ruby core library yet.
 @return [Hash]