def _reshape_for_est(X_del):
    """Convert X_del to a sklearn-compatible shape."""
    n_times, n_epochs, n_feats, n_delays = X_del.shape
    X_del = X_del.reshape(n_times, n_epochs, -1)
    X_del = X_del.reshape(n_times * n_epochs, -1, order='F')
    return X_del
