def subset_spike_time_by_channel(spike_time_labels, channel_id):
    """Subset spike times by specific channel ID
    
    Args:
        spike_time_labels: A numpy array of shape (n_spikes, 2), each row is [time, channel_id]
        channel_id: int, channel_id
    Return:
        a subset of spike_time_labels from a particular channel.
    """
    return spike_time_labels[spike_time_labels[:, 1] == channel_id]