code: def _draw_markers(
      self, ax, element, marks, values, factors, axis="x"
  ):
      if marks is None or self.radial:
          return
      self.param.warning(
          "Only radial HeatMaps supports marks, to make the"
          "HeatMap quads more distinguishable set linewidths"
          "to a non-zero value."
      )
  
imports: from itertools import product
  import numpy
  import param
  from matplotlib.collections import LineCollection, PatchCollection
  from matplotlib.patches import Circle, Wedge
  from ...core.data import GridInterface
  from ...core.spaces import HoloMap
  from ...core.util import dimension_sanitizer, is_nan
  from ..mixins import HeatMapMixin
  from .element import ColorbarPlot
  from .raster import QuadMeshPlot
  from .util import filter_styles
label_desc: Use image node_id 5 for calling the HeatMapPlot obj's underlying member method code with example usage: obj._draw_markers(ax, element, marks, values, factors, axis) without return types