@classmethod
def add_global_scope(cls, scope):
    """
        Register a new global scope on the model.

        :param scope: The scope to register
        :type scope: eloquent.orm.scopes.scope.Scope
        """
    if cls not in cls._global_scopes:
        cls._global_scopes[cls] = {}
    cls._global_scopes[cls][scope.__class__] = scope
