code: def test_eval_type(self):
      self.assertEqual(
          udf(lambda x: str(x), useArrow=True).evalType,
          PythonEvalType.SQL_ARROW_BATCHED_UDF,
      )
      self.assertEqual(
          udf(lambda x: str(x), useArrow=False).evalType,
          PythonEvalType.SQL_BATCHED_UDF,
      )
  
imports: import unittest
  from pyspark.errors import PythonException, PySparkNotImplementedError
  from pyspark.sql import Row
  from pyspark.sql.functions import udf
  from pyspark.sql.tests.test_udf import BaseUDFTestsMixin
  from pyspark.sql.types import VarcharType
  from pyspark.testing.sqlutils import have_pandas, have_pyarrow, pandas_requirement_message, pyarrow_requirement_message, ReusedSQLTestCase
  from pyspark.rdd import PythonEvalType
label_desc: Use image node_id 6 for calling the PythonUDFArrowTestsMixin obj's underlying member method code with example usage: obj.test_eval_type() without return types