code: def aes(x=None, y=None, **other):
      """
      Define aesthetic mappings.
  
      Parameters
      ----------
      x, y, ... :
          List of name value pairs giving aesthetics to map to variables.
          The names for x and y aesthetics are typically omitted because they are so common; all other aesthetics must be named.
  
      Returns
      -------
      `FeatureSpec`
          Aesthetic mapping specification.
  
      Notes
      -----
      Generate aesthetic mappings that describe how variables in the data are projected to visual properties
      (aesthetics) of geometries. This function also standardizes aesthetic names by, for example, converting
      colour to color.
  
      Aesthetic mappings are not to be confused with aesthetic settings; the latter are used to set aesthetics to
      some constant values, e.g. make all points red in the plot. If one wants to make the color of a point
      depend on the value of a variable, he/she should project this variable to the color aesthetic via
      aesthetic mapping.
  
      Examples
      --------
      .. jupyter-execute::
          :linenos:
          :emphasize-lines: 10-11
  
          import numpy as np
          from lets_plot import *
          LetsPlot.setup_html()
          n = 100
          np.random.seed(42)
          x = np.random.uniform(-1, 1, size=n)
          y = 25 * x ** 2 + np.random.normal(size=n)
          c = np.where(x < 0, '0', '1')
          ggplot({'x': x, 'y': y, 'c': c}) + \\
              geom_point(aes('x', 'y', color='y', shape='c', size='x')) + \\
              geom_smooth(aes(x='x', y='y'), deg=2, size=1)
  
      |
  
      .. jupyter-execute::
          :linenos:
          :emphasize-lines: 3-4
  
          from lets_plot import *
          LetsPlot.setup_html()
          ggplot() + geom_polygon(aes(x=[0, 1, 2], y=[2, 1, 4]), \\
                                  color='black', alpha=.5, size=1)
  
      """
  
      return FeatureSpec("mapping", name=None, x=x, y=y, **other)
  
imports: import io
  import json
  import os
  from typing import Union
  from lets_plot._global_settings import get_global_bool, has_global_value, FRAGMENTS_ENABLED
label_desc: Use image node_id 1 for calling a global function with example usage: aes(x, y) and returns: FeatureSpec