code: def test_midpoint():
      p = (
          ggplot(data, aes("x"))
          + geom_histogram(aes(fill="factor(z)"), bins=n, alpha=0.25)
          + geom_freqpoly(bins=n, size=4)
          + geom_point(
              stat="bin", bins=n, size=4, stroke=0, color="red"
          )
      )
  
      assert p == "midpoint"
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_midpoint() without return types