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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def filter_channels_by_status( channel_states: List[NettingChannelState], exclude_states: Optional[List[str]] = None, ) -> List[NettingChannelState]: """ Filter the list of channels by excluding ones for which the state exists in `exclude_states`. """


    if exclude_states is None:
        exclude_states = []

    states = []
    for channel_state in channel_states:
        if channel.get_status(channel_state) not in exclude_states:
            states.append(channel_state)

    return states