code: def test_cumsum():
      for array in arrays:
          s = Stream.source(array, dtype="float")
          w = s.cumsum().rename("w")
          expected = list(pd.Series(array).cumsum())
  
          assert_op([w], expected)
  
imports: import numpy
  import pandas
  from tensortrade.feed import Stream
  from tests.utils.ops import assert_op
label_desc: Use image node_id 1 for calling a global function with example usage: test_cumsum() without return types