code: def test_string_findall(self):
      self.check_func_on_series(
          lambda x: x.str.findall("es|as").apply(str), self.pser[:-1]
      )
      self.check_func_on_series(
          lambda x: x.str.findall("wh.*", flags=re.IGNORECASE).apply(
              str
          ),
          self.pser[:-1],
      )
  
imports: import pandas
  import numpy
  import re
  from pyspark import pandas
  from pyspark.testing.pandasutils import PandasOnSparkTestCase
  from pyspark.testing.sqlutils import SQLTestUtils
label_desc: Use image node_id 9 for calling the SeriesStringOpsAdvMixin obj's underlying member method code with example usage: obj.test_string_findall() without return types