code: def coord_fixed(ratio=1.0, xlim=None, ylim=None, flip=False):
      """
      A fixed scale coordinate system forces a specified ratio between the physical representations of data units on the axes.
  
      Parameters
      ----------
      ratio : float
          The ratio represents the number of units on the y-axis equivalent to one unit on the x-axis.
          ratio = 1, ensures that one unit on the x-axis is the same length as one unit on the y-axis.
          Ratios higher than one make units on the y-axis longer than units on the x-axis, and vice versa.
      xlim : list
          Limits (2 elements) for the x axis.
          1st element defines lower limit, 2nd element defines upper limit.
          None means no lower / upper bound - depending on the index in list.
      ylim : list
          Limits (2 elements) for the y axis.
          1st element defines lower limit, 2nd element defines upper limit.
          None means no lower / upper bound - depending on the index in list.
      flip : bool
          Flip the coordinate system axis so that horizontal axis becomes vertical and vice versa.
  
      Returns
      -------
      `FeatureSpec`
          Coordinate system specification.
  
      Examples
      --------
      .. jupyter-execute::
          :linenos:
          :emphasize-lines: 9
  
          import numpy as np
          from lets_plot import *
          LetsPlot.setup_html()
          n = 30
          np.random.seed(42)
          x = np.random.uniform(-1, 1, size=n)
          y = 25 * x ** 2 + np.random.normal(size=n)
          ggplot({'x': x, 'y': y}, aes(x='x', y='y')) + \\
              geom_point() + coord_fixed(ratio=.2, ylim=(7, 20))
  
      """
  
      return _coord(
          "fixed", ratio=ratio, xlim=xlim, ylim=ylim, flip=flip
      )
  
imports: from .core import FeatureSpec
label_desc: Use image node_id 2 for calling a global function with example usage: coord_fixed(ratio, xlim, ylim, flip) and returns: _coord