def _resample_regressor(hr_regressor, hr_frame_times, frame_times):
    """this function sub-samples the regressors at frame times

    Parameters
    ----------
    hr_regressor : array of shape(n_samples),
        the regressor time course sampled at high temporal resolution
    hr_frame_times : array of shape(n_samples),
        the corresponding time stamps
    frame_times: array of shape(n_scans),
         the desired time stamps

    Returns
    -------
    regressor: array of shape(n_scans)
         the resampled regressor
    """
    from scipy.interpolate import interp1d
    f = interp1d(hr_frame_times, hr_regressor)
    return f(frame_times).T
