code: 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",
      vlim_array=None,
  ):
      """Plot erfimage topography using a single axis."""
      _compute_ax_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, :]
      vmin, vmax = (
          (None, None) if vlim_array is None else vlim_array[ch_idx]
      )
  
      if callable(order):
          order = order(epochs.times, this_data)
  
      if order is not None:
          this_data = this_data[order]
  
      if sigma > 0.0:
          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",
          )
      )
  
imports: from copy import deepcopy
  from functools import partial
  import numpy
  from scipy import ndimage
  from .._fiff.pick import channel_type, pick_types
  from ..defaults import _handle_default
  from ..utils import Bunch, _check_option, _clean_names, _is_numeric, _to_rgb, fill_doc
  from .utils import DraggableColorbar, _check_cov, _check_delayed_ssp, _draw_proj_checkbox, _plot_masked_image, _setup_ax_spines, _setup_vmin_vmax, add_background_image, plt_show
label_desc: Use image node_id 13 for calling a global function with example usage: _erfimage_imshow_unified(bn, ch_idx, tmin, tmax, vmin, vmax, ylim, data, epochs, sigma, order, scalings, vline, x_label, y_label, colorbar, cmap, vlim_array) without return types