code: def test_step():
      p = (
          ggplot(data, aes("x"))
          + geom_step(aes(y="y"), size=4)
          + geom_step(aes(y="y+2"), color="red", direction="vh", size=4)
      )
  
      assert p == "step"
  
file_path: plotnine/tests/test_geom_path_line_step.py
imports: import numpy
  import pandas
  import pytest
  from plotnine import aes, arrow, facet_grid, geom_line, geom_path, geom_point, geom_step, ggplot
  from plotnine.exceptions import PlotnineWarning
label_desc: Use image node_id 4 for calling a global function with example usage: test_step() without return types