code: def test_drop_fields(self):
      df = self.spark.createDataFrame(
          [Row(a=Row(b=1, c=2, d=Row(e=3, f=4)))]
      )
      self.assertIsInstance(df["a"].dropFields("b"), Column)
      self.assertIsInstance(df["a"].dropFields("b", "c"), Column)
      self.assertIsInstance(df["a"].dropFields("d.e"), Column)
  
      result = (
          df.select(
              df["a"].dropFields("b").alias("a1"),
              df["a"].dropFields("d.e").alias("a2"),
          )
          .first()
          .asDict(True)
      )
  
      self.assertTrue(
          "b" not in result["a1"]
          and "c" in result["a1"]
          and "d" in result["a1"]
      )
  
      self.assertTrue(
          "e" not in result["a2"]["d"] and "f" in result["a2"]["d"]
      )
  
imports: from itertools import chain
  from pyspark.sql import Column, Row
  from pyspark.sql import functions
  from pyspark.sql.types import StructType, StructField, LongType
  from pyspark.errors import AnalysisException, PySparkTypeError, PySparkValueError
  from pyspark.testing.sqlutils import ReusedSQLTestCase
label_desc: Use image node_id 12 for calling the ColumnTestsMixin obj's underlying member method code with example usage: obj.test_drop_fields() without return types