code: def test_rolling_std():
      for array, config in product(arrays, configurations):
          s = Stream.source(array, dtype="float")
          w = s.rolling(**config).std().rename("w")
          expected = list(pd.Series(array).rolling(**config).std())
  
          assert_op([w], expected)
  
file_path: tensortrade/tests/tensortrade/unit/feed/api/float/window/test_rolling.py
imports: from itertools import product
  import pytest
  import numpy
  import pandas
  from tensortrade.feed import Stream
  from tests.utils.ops import assert_op
label_desc: Use image node_id 6 for calling a global function with example usage: test_rolling_std() without return types