code: def test_axvspan(self):
      mpl.rcParams["date.converter"] = "concise"
  
      start_date = datetime.datetime(2023, 1, 1)
      dates = [
          start_date + datetime.timedelta(days=i) for i in range(31)
      ]
      numbers = list(range(1, 32))
  
      fig, (ax1, ax2, ax3) = plt.subplots(
          3, 1, constrained_layout=True, figsize=(10, 12)
      )
  
      ax1.plot(dates, numbers, marker="o", color="blue")
      for i in range(0, 31, 2):
          xmin = start_date + datetime.timedelta(days=i)
          xmax = xmin + datetime.timedelta(days=1)
          ax1.axvspan(xmin=xmin, xmax=xmax, facecolor="red", alpha=0.5)
      ax1.set_title("Datetime vs. Number")
      ax1.set_xlabel("Date")
      ax1.set_ylabel("Number")
  
      ax2.plot(numbers, dates, marker="o", color="blue")
      for i in range(0, 31, 2):
          ax2.axvspan(
              xmin=i + 1, xmax=i + 2, facecolor="red", alpha=0.5
          )
      ax2.set_title("Number vs. Datetime")
      ax2.set_xlabel("Number")
      ax2.set_ylabel("Date")
  
      ax3.plot(dates, dates, marker="o", color="blue")
      for i in range(0, 31, 2):
          xmin = start_date + datetime.timedelta(days=i)
          xmax = xmin + datetime.timedelta(days=1)
          ax3.axvspan(xmin=xmin, xmax=xmax, facecolor="red", alpha=0.5)
      ax3.set_title("Datetime vs. Datetime")
      ax3.set_xlabel("Date")
      ax3.set_ylabel("Date")
  
imports: import datetime
  import numpy
  import pytest
  import matplotlib.pyplot
  import matplotlib
label_desc: Use image node_id 7 for calling the TestDatetimePlotting obj's underlying member method code with example usage: obj.test_axvspan() without return types