code: def _get_markers(ticks, marker):
      if callable(marker):
          marks = [v for v, l in ticks if marker(l)]
      elif isinstance(marker, int) and marker:
          nth_mark = max([np.ceil(len(ticks) / marker).astype(int), 1])
          marks = [v for v, l in ticks[::nth_mark]]
      elif isinstance(marker, tuple):
          marks = [v for v, l in ticks if l in marker]
      else:
          marks = []
      return marks
  
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 3 for calling the RadialHeatMapPlot obj's underlying member method code with example usage: obj._get_markers(ticks, marker) and returns: marks