code: def _validate_linestyles_pce(linestyles, conditions, tags):
      """Check and assign linestyles for plot_compare_evokeds."""
      # make linestyles a list if it's not defined
      if linestyles is None:
          linestyles = [None] * len(
              conditions
          )  # will get changed to defaults
      # convert linestyle list to dict
      if isinstance(linestyles, (list, tuple, np.ndarray)):
          if len(conditions) > len(linestyles):
              raise ValueError(
                  f"Trying to plot {len(conditions)} conditions, but there are only "
                  f"{len(linestyles)} linestyles. Please specify linestyles manually."
              )
          linestyles = dict(zip(conditions, linestyles))
      # should be a dict by now...
      if not isinstance(linestyles, dict):
          raise TypeError(
              '"linestyles" must be a dict, list, or None; got {}.'.format(
                  type(linestyles).__name__
              )
          )
      # validate linestyle dict keys
      if not set(linestyles).issubset(tags.union(conditions)):
          raise ValueError(
              f'If "linestyles" is a dict its keys ({list(linestyles)}) must match the '
              f'keys/conditions in "evokeds" ({conditions}).'
          )
      # normalize linestyle values (so we can accurately count unique linestyles
      # later). See https://github.com/matplotlib/matplotlib/blob/master/matplotlibrc.template#L131-L133  # noqa
      linestyle_map = {
          "solid": (0, ()),
          "dotted": (0, (1.0, 1.65)),
          "dashed": (0, (3.7, 1.6)),
          "dashdot": (0, (6.4, 1.6, 1.0, 1.6)),
          "-": (0, ()),
          ":": (0, (1.0, 1.65)),
          "--": (0, (3.7, 1.6)),
          "-.": (0, (6.4, 1.6, 1.0, 1.6)),
      }
      for cond, _ls in linestyles.items():
          linestyles[cond] = linestyle_map.get(_ls, _ls)
      return linestyles
  
imports: from copy import deepcopy
  from functools import partial
  from itertools import cycle
  from numbers import Integral
  import numpy
  from .._fiff.pick import _DATA_CH_TYPES_SPLIT, _PICK_TYPES_DATA_DICT, _VALID_CHANNEL_TYPES, _picks_to_idx, channel_indices_by_type, channel_type, pick_info
  from ..defaults import _handle_default
  from ..fixes import _is_last_row
  from ..utils import _check_ch_locs, _check_if_nan, _clean_names, _is_numeric, _pl, _to_rgb, _validate_type, fill_doc, logger, verbose, warn
  from .topo import _plot_evoked_topo
  from .topomap import _check_sphere, _draw_outlines, _get_pos_outlines, _make_head_outlines, _prepare_topomap, _prepare_topomap_plot, _set_contour_locator, plot_topomap
  from .utils import DraggableColorbar, _check_cov, _check_delayed_ssp, _check_option, _check_time_unit, _draw_proj_checkbox, _get_cmap, _get_color_list, _make_combine_callable, _plot_masked_image, _prepare_joint_axes, _process_times, _prop_kw, _set_title_multiple_electrodes, _set_window_title, _setup_ax_spines, _setup_cmap, _setup_plot_projector, _setup_vmin_vmax, _triage_rank_sss, _trim_ticks, _validate_if_list_of_axes, plt_show
label_desc: Use image node_id 24 for calling a global function with example usage: _validate_linestyles_pce(linestyles, conditions, tags) and returns: linestyles