code: def test_stairs(self):
      mpl.rcParams["date.converter"] = "concise"
  
      start_date = datetime.datetime(2023, 12, 1)
      time_delta = datetime.timedelta(days=1)
      baseline_date = datetime.datetime(1980, 1, 1)
  
      bin_edges = [start_date + i * time_delta for i in range(31)]
      edge_int = np.arange(31)
      np.random.seed(123456)
      values1 = np.random.randint(1, 100, 30)
      values2 = [
          start_date + datetime.timedelta(days=int(i))
          for i in np.random.randint(1, 10000, 30)
      ]
      values3 = [
          start_date + datetime.timedelta(days=int(i))
          for i in np.random.randint(-10000, 10000, 30)
      ]
  
      fig, (ax1, ax2, ax3) = plt.subplots(3, 1, constrained_layout=True)
      ax1.stairs(values1, edges=bin_edges)
      ax2.stairs(values2, edges=edge_int, baseline=baseline_date)
      ax3.stairs(values3, edges=bin_edges, baseline=baseline_date)
  
imports: import datetime
  import numpy
  import pytest
  import matplotlib.pyplot
  import matplotlib
label_desc: Use image node_id 40 for calling the TestDatetimePlotting obj's underlying member method code with example usage: obj.test_stairs() without return types