code: def test_cov(self):
      self.check((2, 3))
      self.check((2,), (2,))
      self.check((1, 3), (1, 3), rowvar=False)
      self.check((2, 3), (2, 3), rowvar=False)
      self.check((2, 3), bias=True)
      self.check((2, 3), ddof=2)
      self.check((2, 3))
      self.check((1, 3), fweights=(1, 4, 1))
      self.check((1, 3), aweights=(1.0, 4.0, 1.0))
      self.check((1, 3), bias=True, aweights=(1.0, 4.0, 1.0))
      self.check((1, 3), fweights=(1, 4, 1), aweights=(1.0, 4.0, 1.0))
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 5 for calling the TestCov obj's underlying member method code with example usage: obj.test_cov() without return types