docstr: Supply custom, static extents because radial heatmaps always have
  the same boundaries.
code: def get_extents(self, view, ranges, range_type="combined", **kwargs):
      """Supply custom, static extents because radial heatmaps always have
      the same boundaries.
      """
      if range_type not in ("data", "combined"):
          return (None,) * 4
      lower = -self.radius_outer
      upper = 2 * self.max_radius + self.radius_outer
      return (lower, lower, upper, upper)
  
imports: import numpy
  import param
  from bokeh.models.glyphs import AnnularWedge
  from ...core.data import GridInterface
  from ...core.spaces import HoloMap
  from ...core.util import dimension_sanitizer, is_nan
  from .element import ColorbarPlot, CompositeElementPlot
  from .selection import BokehOverlaySelectionDisplay
  from .styles import base_properties, fill_properties, line_properties, text_properties
label_desc: Use image node_id 5 for calling the RadialHeatMapPlot obj's underlying member method code with example usage: obj.get_extents(view, ranges, range_type) and returns: lower,  lower,  upper,  upper, unknown