docstr: Add an arrow in the main graph between the methods
  
  Parameters
  ----------
  ax : ax
      Input ax used for the plot
  a : array
      Coordinates of method 1
  b : array
      Coordinates of method 2
  dst : float
      Distance between the methods
docstr_tok: ["Add","an","arrow","in","the","main","graph","between","the","methods","Parameters","--","--","--","--","--","ax",":","ax","Input","ax","used","for","the","plot","a",":","array","Coordinates","of","method","1","b",":","array","Coordinates","of","method","2","dst",":","float","Distance","between","the","methods"]
code: def draw_arrow(self, ax, a, b, dst):
      """
      Add an arrow in the main graph between the methods
  
      Parameters
      ----------
      ax : ax
          Input ax used for the plot
      a : array
          Coordinates of method 1
      b : array
          Coordinates of method 2
      dst : float
          Distance between the methods
      """
      ax.annotate(
          "",
          xy=a - 0.05 * (a - b),
          xycoords="data",
          xytext=b + 0.05 * (a - b),
          textcoords="data",
          arrowprops=dict(arrowstyle="<->"),
      )
      ax.annotate(
          "%.2f" % dst,
          xy=(0.5 * (a[0] + b[0]), 0.5 * (a[1] + b[1])),
          xycoords="data",
          textcoords="data",
          ha="center",
      )
  
imports: from category_encoders import OrdinalEncoder
  import copy
  import itertools
  import matplotlib.pyplot
  import numpy
  import pandas
  from plotly import graph_objs
  from plotly.offline import plot
  from plotly.subplots import make_subplots
  from sklearn.manifold import MDS
  from shapash import SmartExplainer
  from shapash.style.style_utils import colors_loading, select_palette, define_style
label_desc: Use image node_id 12 for calling the Consistency obj's underlying member method code with example usage: obj.draw_arrow(ax, a, b, dst) without return types