how to use assert_frame_equal in unittest

New to unittest package. I'm trying to verify the DataFrame returned by a function through the following code. Even though I hardcoded the inputs of assert_frame_equal to be equal (pd.DataFrame([0,0,0,0])), the unittest still fails. Anyone would like to explain why it happens?

import unittest
from pandas.util.testing import assert_frame_equal
class TestSplitWeight(unittest.TestCase):
    def test_allZero(self):
        #splitWeight(pd.DataFrame([0,0,0,0]),10)
        self.assert_frame_equal(pd.DataFrame([0,0,0,0]),pd.DataFrame([0,0,0,0]))

suite = unittest.TestLoader().loadTestsFromTestCase(TestSplitWeight)
unittest.TextTestRunner(verbosity=2).run(suite)

Error: AttributeError: 'TestSplitWeight' object has no attribute 'assert_frame_equal'