Adds the path to the extension to a list that will be used to extract it
        to the ChromeDriver

        :Args:
         - extension: path to the \\*.crx file

def add_extension(self, extension):
        """
        Adds the path to the extension to a list that will be used to extract it
        to the ChromeDriver

        :Args:
         - extension: path to the \\*.crx file
        """
        if extension:
            extension_to_add = os.path.abspath(os.path.expanduser(extension))
            if os.path.exists(extension_to_add):
                self._extension_files.append(extension_to_add)
            else:
                raise IOError("Path to the extension doesn't exist")
        else:
            raise ValueError("argument can not be null")