code: def test_as_series_list(self, xp, dtype):
      a = [xp.array([3, 5, 7, -4, 1, 2]).astype(dtype)]
      return xp.polynomial.polyutils.as_series(a, trim=self.trim)
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 4 for calling the TestAsSeries obj's underlying member method code with example usage: obj.test_as_series_list(xp, dtype) and returns: xp