input: Write a python function to create a 3D numpy array of zeros with the given dimensions.
  assert np.array_equal(create_3d_zeros_array(2, 3, 2), np.zeros((2, 3, 2)))
  assert np.array_equal(create_3d_zeros_array(4, 5, 6), np.zeros((4, 5, 6)))
  assert np.array_equal(create_3d_zeros_array(1, 1, 1), np.zeros((1, 1, 1)))
output: import numpy as np
  
  def create_3d_zeros_array(x, y, z):
      return np.zeros((x, y, z))