code: def test_facet_grid_one_by_one_var():
      p = g + facet_grid("var1~var2")
      p2 = g + facet_grid("class~var2")  # python keyword in formula
      assert p == "facet_grid_one_by_one_var"
      assert p2 == "facet_grid_one_by_one_var"
  
imports: import numpy
  import pandas
  from plotnine import aes, annotate, facet_grid, facet_wrap, geom_abline, geom_path, geom_point, ggplot
  from plotnine.data import mpg, mtcars
label_desc: Use image node_id 8 for calling a global function with example usage: test_facet_grid_one_by_one_var() without return types