code: def array_df_cols(self):
      return self.array_pdf.columns
  
imports: import decimal
  import datetime
  import pandas
  from pyspark import pandas
  from pyspark.testing.pandasutils import PandasOnSparkTestCase
  from pyspark.pandas.tests.data_type_ops.testing_utils import OpsTestBase
label_desc: Use image node_id 11 for calling the ComplexOpsTestsMixin obj's underlying member method code with example usage: obj.array_df_cols() and returns: self