code: def pdf4(self):
      np.random.seed(33)
      index = pd.date_range(
          start="2020-12-12", end="2022-05-01", freq="1H"
      )
      return pd.DataFrame(
          np.random.rand(len(index), 2), index=index, columns=list("AB")
      )
  
imports: import unittest
  import datetime
  import numpy
  import pandas
  from pyspark import pandas
  from pyspark.testing.pandasutils import PandasOnSparkTestCase, TestUtils
label_desc: Use image node_id 4 for calling the ResampleFrameMixin obj's underlying member method code with example usage: obj.pdf4() and returns: pd