code: def test_abs(self):
      pdf = pd.DataFrame({"a": [-2, -1, 0, 1]})
      psdf = ps.from_pandas(pdf)
  
      self.assert_eq(abs(psdf), abs(pdf))
      self.assert_eq(np.abs(psdf), np.abs(pdf))
  
imports: import unittest
  import numpy
  import pandas
  from pyspark.sql import functions
  from pyspark import pandas
  from pyspark.testing.pandasutils import ComparisonTestBase
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 3 for calling the FrameComputeMixin obj's underlying member method code with example usage: obj.test_abs() without return types