code: def test_empty_plot():
      """Test making a plot with empty arrays."""
      fig = plt.figure()
      ax = plt.axes(projection=ccrs.Mercator())
      ax.plot([], [], transform=ccrs.PlateCarree())
      fig.savefig(BytesIO())
  
imports: from io import BytesIO
  import matplotlib.pyplot
  import numpy
  import cartopy.crs
label_desc: Use image node_id 1 for calling a global function with example usage: test_empty_plot() without return types