def _prep_behavior(dataset, lag, make_params):
    """Helper function that makes separate make_params 
    for behavioral data

    Parameters
    ----------
    dataset : NWBDataset
        NWBDataset that the make_params are made for
    lag : int
        Amount that behavioral data is lagged relative to
        trial alignment in `make_params`
    make_params : dict
        Arguments for `NWBDataset.make_trial_data`
        to extract trialized data
    
    Returns
    -------
    dict
        Arguments for `NWBDataset.make_trial_data`
        to extract trialized behavior data
    """
    behavior_make_params = make_params.copy()
    if lag is not None:
        behavior_make_params['allow_nans'] = True
        if 'align_range' in behavior_make_params:
            behavior_make_params['align_range'] = tuple([(t + lag) for t in make_params['align_range']])
        else:
            behavior_make_params['align_range'] = (lag, lag)
    else:
        behavior_make_params = None
    return behavior_make_params