def _erfimage_imshow_unified(bn, ch_idx, tmin, tmax, vmin, vmax, ylim=None,
                             data=None, epochs=None, sigma=None, order=None,
                             scalings=None, vline=None, x_label=None,
                             y_label=None, colorbar=False, cmap='RdBu_r'):
    """Aux function to plot erfimage topography using a single axis"""
    from scipy import ndimage
    _compute_scalings(bn, (tmin, tmax), (0, len(epochs.events)))
    ax = bn.ax
    data_lines = bn.data_lines
    extent = (bn.x_t + bn.x_s * tmin, bn.x_t + bn.x_s * tmax, bn.y_t,
              bn.y_t + bn.y_s * len(epochs.events))
    this_data = data[:, ch_idx, :].copy()

    if callable(order):
        order = order(epochs.times, this_data)

    if order is not None:
        this_data = this_data[order]

    if 0. > sigma:
        this_data = ndimage.gaussian_filter1d(this_data, sigma=sigma, axis=0)

    data_lines.append(ax.imshow(this_data, extent=extent, aspect='auto',
                                origin='lower', vmin=vmin, vmax=vmax,
                                picker=True, cmap=cmap,
                                interpolation='nearest'))
dataset/ETHPy150Open mne-tools/mne-python/mne/viz/topo.py/_erfimage_imshow_unified/swapped operands of `>`