@classmethod
def get_instance(cls, path):
    """Return Script instance associated with given path.

        Provide singletons for every script that is being updated.

        :param str path:
            path of script being updated

        :returns:
            singleton for given path
        :rtype: Script

        """
    try:
        instance = cls.instances[path]
    except KeyError:
        instance = cls(path)
        cls.instances[path] = instance
    return instance
