code: def test_fill_method_bfill(self):
      primitive_instance = SameAsPrevious(fill_method="bfill")
      primitive_func = primitive_instance.get_function()
      array = pd.Series([1, np.nan, 3, 2, 2], dtype="float64")
      answer = primitive_func(array)
      correct_answer = pd.Series([False, False, True, False, True])
      np.testing.assert_array_equal(answer, correct_answer)
  
file_path: featuretools/featuretools/tests/primitive_tests/transform_primitive_tests/test_same_as_previous.py
imports: import numpy
  import pandas
  import pytest
  from featuretools.primitives import SameAsPrevious
label_desc: Use image node_id 9 for calling the TestSameAsPrevious obj's underlying member method code with example usage: obj.test_fill_method_bfill() without return types