code: def test_none_channels_mean():
      # 3-D image
      fn = mean_filter2d.get_concrete_function(
          tf.TensorSpec(dtype=tf.dtypes.float32, shape=(3, 3, None))
      )
      fn(tf.ones(shape=(3, 3, 1)))
      fn(tf.ones(shape=(3, 3, 3)))
  
      # 4-D image
      fn = mean_filter2d.get_concrete_function(
          tf.TensorSpec(dtype=tf.dtypes.float32, shape=(1, 3, 3, None))
      )
      fn(tf.ones(shape=(1, 3, 3, 1)))
      fn(tf.ones(shape=(1, 3, 3, 3)))
  
imports: import pytest
  import numpy
  import tensorflow
  from tensorflow_addons.image import mean_filter2d
  from tensorflow_addons.image import median_filter2d
  from tensorflow_addons.image import gaussian_filter2d
  from tensorflow_addons.utils import test_utils
  from scipy.ndimage.filters import gaussian_filter
label_desc: Use image node_id 7 for calling a global function with example usage: test_none_channels_mean() without return types