text: import numpy as np
  
  from plot import plt
  
  
  def plot_day_lines(datetimes):
      """Plot a vertical line every 00:00. You still have to call plt.legend."""
      label_set = False
      for dt in datetimes:
          if np.isclose(float(dt.hour + dt.minute), 0):
              label = None
              if not label_set:
                  label = "Time = 00:00"
                  label_set = True
              plt.axvline(x=dt, linewidth=1, color="black", label=label)
  