code: def _prepare_box_data(self, df):
      xs = sorted(df["x"].unique())
      ys = []
      for x in xs:
          ys.append(df[df["x"] == x]["y"].values)
      return xs, ys
  
imports: from .styles import _prepare_plot_style, _axes_modify, _display_percentile, _modify_legend_axes, _get_axes_label
  import numpy
  from itertools import cycle
  import plotly.express
  import matplotlib
  import matplotlib.pyplot
  from matplotlib.gridspec import GridSpecFromSubplotSpec
  from mpl_toolkits.axes_grid1.inset_locator import inset_axes
  import matplotlib.patheffects
  import plotly.graph_objects
label_desc: Use image node_id 6 for calling the InfoPlotEngine obj's underlying member method code with example usage: obj._prepare_box_data(df) and returns: xs,  ys