code: def test_get_symbol():
      x = mx.nd.ones((1,))
      x.attach_grad()
      with record():
          y = x * x + 2 * x - 1
      assert len(get_symbol(y).list_arguments()) == 1
  
      z = mx.nd.ones((1,))
      z.attach_grad()
      with record():
          y = x * x + 2 * z - 1
      assert len(get_symbol(y).list_arguments()) == 2
  
imports: import functools
  import mxnet.ndarray
  from mxnet.ndarray import zeros_like
  from mxnet.autograd import *
  from mxnet.test_utils import *
  from common import xfail_when_nonstandard_decimal_separator
  from mxnet.test_utils import environment
  import pytest
label_desc: Use image node_id 18 for calling a global function with example usage: test_get_symbol() without return types