code: def class_form():
      dt = 1.0
      std_z = 10.1
  
      f = const_vel_filter(dt, x0=2, R_std=std_z, Q_std=5.1)
  
      pos = 0.0
      for t in range(2000):
          z = pos + random.randn() * std_z
          pos += 100
  
          f.predict()
          f.update(z)
  
imports: from __future__ import absolute_import, division, print_function
  import numpy.random
  from numpy.random import randn
  import numpy
  import matplotlib.pyplot
  from pytest import approx
  from filterpy.kalman import KalmanFilter, update, predict, batch_filter
  from filterpy.common import Q_discrete_white_noise, kinematic_kf, Saver
  from filterpy.stats import mahalanobis
  from scipy.linalg import block_diag, norm
label_desc: Use image node_id 13 for calling a global function with example usage: class_form() without return types