code: def test_esn_connectivity():
      units = 1000
      connectivity = 0.5
      cell = ESNCell(
          units=units,
          connectivity=connectivity,
          use_norm2=True,
          recurrent_initializer="ones",
      )
      cell.build((3, 3))
      recurrent_weights = tf.constant(cell.get_weights()[0])
      num_non_zero = tf.math.count_nonzero(recurrent_weights)
      actual_connectivity = tf.divide(num_non_zero, units**2)
      np.testing.assert_allclose(
          np.asarray([actual_connectivity]),
          np.asanyarray([connectivity]),
          1e-2,
      )
  
file_path: addons/tensorflow_addons/rnn/tests/esn_cell_test.py
imports: import numpy
  import tensorflow
  import tensorflow.keras
  from tensorflow_addons.rnn import ESNCell
label_desc: Use image node_id 4 for calling a global function with example usage: test_esn_connectivity() without return types