code: def _imshow_tfr_unified(
      bn,
      ch_idx,
      tmin,
      tmax,
      vmin,
      vmax,
      onselect,
      ylim=None,
      tfr=None,
      freq=None,
      vline=None,
      x_label=None,
      y_label=None,
      colorbar=False,
      picker=True,
      cmap="RdBu_r",
      title=None,
      hline=None,
  ):
      """Show multiple tfrs on topo using a single axes."""
      _compute_ax_scalings(bn, (tmin, tmax), (freq[0], freq[-1]))
      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_s * freq[0],
          bn.y_t + bn.y_s * freq[-1],
      )
      data_lines.append(
          ax.imshow(
              tfr[ch_idx],
              extent=extent,
              aspect="auto",
              origin="lower",
              vmin=vmin,
              vmax=vmax,
              cmap=cmap,
          )
      )
      data_lines[-1].set_clip_box(_pos_to_bbox(bn.pos, ax))
  
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 9 for calling a global function with example usage: _imshow_tfr_unified(bn, ch_idx, tmin, tmax, vmin, vmax, onselect, ylim, tfr, freq, vline, x_label, y_label, colorbar, picker, cmap, title, hline) without return types