def __init__(self, flow, process, instance, name, **kwargs):
    wait_for = kwargs.pop('wait_for', None)
    if (not wait_for):
        raise ValueError('Wait activity needs to wait for something.')
    super(Wait, self).__init__(flow, process, instance, name, **kwargs)
    self._wait_for = (set(wait_for) if wait_for else None)
def __init__(self, flow, process, instance, name, **kwargs):
    wait_for = kwargs.pop('wait_for', None)
    if (not wait_for):
        raise ValueError('Wait activity needs to wait for something.')
    super(Wait, self).__init__(flow, process, instance, name, **kwargs)
    self._wait_for = (set(wait_for) if wait_for else None)