docstr: Get factors for categorical axes.
code: def _get_factors(self, element, ranges):
      """
      Get factors for categorical axes.
      """
      split_dim = (
          dim(self.split) if isinstance(self.split, str) else self.split
      )
      kdims = [
          kd
          for kd in element.kdims
          if not split_dim or kd != split_dim.dimension
      ]
      if not kdims:
          xfactors, yfactors = [element.label], []
      else:
          factors = [key for key in element.groupby(kdims).data.keys()]
          if element.ndims > 1:
              factors = sorted(factors)
          factors = [
              tuple(d.pprint_value(k) for d, k in zip(kdims, key))
              for key in factors
          ]
          factors = [f[0] if len(f) == 1 else f for f in factors]
          xfactors, yfactors = factors, []
      return (
          (yfactors, xfactors)
          if self.invert_axes
          else (xfactors, yfactors)
      )
  
imports: from collections import defaultdict
  from functools import partial
  import numpy
  import param
  from bokeh.models import Circle, FactorRange, HBar, VBar
  from ...core import NdOverlay
  from ...core.dimension import Dimension, Dimensioned
  from ...core.ndmapping import sorted_context
  from ...core.util import dimension_sanitizer, is_cupy_array, is_dask_array, isfinite, unique_iterator, wrap_tuple
  from ...operation.stats import univariate_kde
  from ...util.transform import dim
  from ..mixins import MultiDistributionMixin
  from .chart import AreaPlot
  from .element import ColorbarPlot, CompositeElementPlot, LegendPlot
  from .path import PolygonPlot
  from .selection import BokehOverlaySelectionDisplay
  from .styles import base_properties, fill_properties, line_properties
  from .util import decode_bytes
label_desc: Use image node_id 2 for calling the ViolinPlot obj's underlying member method code with example usage: obj._get_factors(element, ranges) and returns: unknown