code: def after_scale(x):
      """
      Evaluate mapping after variable has been mapped to the scale
  
      This gives the user a chance to alter the value of a variable
      in the final units of the scale e.g. the rgb hex color.
  
      Parameters
      ----------
      x : str
          An expression
  
      See Also
      --------
      plotnine.mapping.after_stat
      plotnine.mapping.stage
      """
      return stage(after_scale=x)
  
file_path: plotnine/plotnine/mapping/evaluation.py
imports: from __future__ import annotations
  import numbers
  import typing
  import numpy
  import pandas
  import pandas.api.types
  from ..exceptions import PlotnineError
label_desc: Use image node_id 2 for calling a global function with example usage: after_scale(x) and returns: stage