code: def test_imshow_rgb():
      # tests that the alpha of a RGB array passed to imshow is set to 0
      # instead of masked
      z = np.full((100, 100, 3), 0.5)
      plt_crs = ccrs.LambertAzimuthalEqualArea()
      latlon_crs = ccrs.PlateCarree()
      ax = plt.axes(projection=plt_crs)
      ax.set_extent([-30, -20, 60, 70], crs=latlon_crs)
      img = ax.imshow(
          z, extent=[-26, -24, 64, 66], transform=latlon_crs
      )
      assert sum(img.get_array().data[:, 0, 3]) == 0
  
imports: import types
  import matplotlib.colors
  import matplotlib.pyplot
  import numpy
  from PIL import Image
  import pytest
  import shapely.geometry
  from cartopy import config
  import cartopy.crs
  import cartopy.io.img_tiles
  from cartopy.tests.conftest import _HAS_PYKDTREE_OR_SCIPY
  import cartopy.tests.test_img_tiles
label_desc: Use image node_id 8 for calling a global function with example usage: test_imshow_rgb() without return types