class_docstr: python reference implemenation of sgd
docstr: Create additional optimizer state: momentum
  
  Parameters
  ----------
  weight : NDArray
  The weight data
docstr_tok: ["Create","additional","optimizer","state",":","momentum","Parameters","--","--","--","--","--","weight",":","NDArray","The","weight","data"]
code: def create_state(self, index, weight):
      """Create additional optimizer state: momentum
  
      Parameters
      ----------
      weight : NDArray
      The weight data
  
      """
      if self.momentum == 0.0:
          return None
      else:
          return mx.nd.zeros(
              weight.shape, weight.context, dtype=weight.dtype
          )
  
imports: import itertools
  import numpy
  import itertools
  import mxnet
  import mxnet.lr_scheduler
  from mxnet import gluon
  import unittest
  import pytest
  import math
  from mxnet.test_utils import *
  from common import retry, xfail_when_nonstandard_decimal_separator
label_desc: Use image node_id 2 for calling the PySparseSGD obj's underlying member method code with example usage: obj.create_state(index, weight) and returns: None, mx