code: def testMomentumVectorInverseTimeDecayStaircaseSchedule(self):
      def loss(x):
          return jnp.dot(x, x)
  
      x0 = jnp.ones(2)
      step_sched = optimizers.inverse_time_decay(
          0.1, 3, 2.0, staircase=True
      )
      mass = 0.9
      self._CheckFuns(optimizers.momentum, loss, x0, step_sched, mass)
  
imports: import functools
  from absl.testing import absltest
  import numpy
  import jax.numpy
  import jax._src.test_util
  from jax import jit, grad, jacfwd, jacrev
  from jax import tree_util
  from jax import lax
  from jax.example_libraries import optimizers
  from jax import config
label_desc: Use image node_id 19 for calling the OptimizerTests obj's underlying member method code with example usage: obj.testMomentumVectorInverseTimeDecayStaircaseSchedule() and returns: jnp