code: def _lines_to_coords(
      lines: LineReturn_ChunkCombinedNan,
  ) -> SingleLineCoords:
      # Processes line data returned from a single call to
      # contourpy.ContourGenerator.lines(level).
      # ContourPy line data format is LineType.ChunkCombinedNan.
      points = lines[0][0]
      if points is None:
          empty = np.empty(0)
          return SingleLineCoords(empty, empty)
  
      xs = points[:, 0]
      ys = points[:, 1]
      return SingleLineCoords(xs, ys)
  
imports: from __future__ import annotations
  import logging
  from typing import TYPE_CHECKING, Sequence, Union, cast
  import numpy
  from ..core.property_mixins import FillProps, HatchProps, LineProps
  from ..models.glyphs import MultiLine, MultiPolygons
  from ..models.renderers import ContourRenderer, GlyphRenderer
  from ..models.sources import ColumnDataSource
  from ..palettes import interp_palette
  from ..plotting._renderer import _process_sequence_literals
  from ..util.dataclasses import dataclass, entries
label_desc: Use image node_id 6 for calling a global function with example usage: _lines_to_coords(lines) and returns: SingleLineCoords, SingleLineCoords