code: def test_summary_functions():
      p = ggplot(data, aes("x", "y")) + stat_summary(
          fun_y=np.mean, fun_ymin=np.min, fun_ymax=np.max, size=2
      )
  
      assert p == "summary_functions"
  
file_path: plotnine/tests/test_stat_summary.py
imports: import numpy
  import pandas
  import pytest
  from plotnine import aes, geom_point, ggplot, stat_summary
label_desc: Use image node_id 7 for calling a global function with example usage: test_summary_functions() without return types