input: Write a python function to create a 3D scatter plot using matplotlib.
  assert create_3Dscatterplot([0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3]) is None
  assert create_3Dscatterplot([1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4]) is None
output: def create_3Dscatterplot(x, y, z):
      import matplotlib.pyplot as plt
      from mpl_toolkits.mplot3d import Axes3D
  
      fig = plt.figure()
      ax = fig.add_subplot(111, projection='3d')
  
      ax.scatter(x, y, z)
  
      plt.show()