code: def __get_scales(max_num_groups):
      """Creates an Altair scale for the color of the parity test result, and another
      for the x axis of the group circles subplot."""
  
      scales = dict()
  
      # COLOR
      scales["color"] = alt.Scale(
          domain=["Reference", "Pass", "Fail"],
          range=Parity_Result.color_palette,
      )
  
      # GROUP CIRCLES X AXIS
      scales["circles_x"] = alt.Scale(
          domain=[-max_num_groups, max_num_groups], nice=False
      )
  
      return scales
  
imports: import altair
  import pandas
  from aequitas.plot.commons.helpers import no_axis, transform_ratio, format_number, get_chart_metadata
  from aequitas.plot.commons.tooltips import get_tooltip_text_group_size, get_tooltip_text_disparity_explanation, get_tooltip_text_parity_test_explanation
  from aequitas.plot.commons.style.classes import Title, Subtitle, Parity_Result, Annotation, Legend
  from aequitas.plot.commons.style.text import FONT
  from aequitas.plot.commons.style.sizes import Summary_Chart
  from aequitas.plot.commons import initializers
  from aequitas.plot.commons import validators
  from aequitas.plot.commons import labels
label_desc: Use image node_id 1 for calling a global function with example usage: __get_scales(max_num_groups) and returns: scales