code: def to_pandas(
      df: "DataFrame",
      squeeze: bool = False,
      index_col: Optional[str] = None,
      dtype: Optional[
          Union[
              str,
              Dict[str, Type[float32]],
              Dict[int, Union[Type[float32], Type[int32]]],
              Dict[str, str],
          ]
      ] = None,
      index_map: Optional[Dict[int, str]] = None,
      batch_size: Optional[int] = None,
  ) -> "RDD":
      def farrow(iter):
          for fileName in iter:
              from pyspark.sql.pandas.serializers import (
                  ArrowStreamSerializer,
              )
              import pyarrow as pa
  
              ser = ArrowStreamSerializer()
              with open(fileName, "rb") as stream:
                  batches = list(ser.load_stream(stream))
                  if len(batches) > 0:
                      table = pa.Table.from_batches(batches)
                      pd_df = table.to_pandas()
                      pd_df = set_pandas_df_type_index(
                          pd_df, squeeze, index_col, dtype, index_map
                      )
                      yield pd_df
                  else:
                      invalidInputError(
                          False,
                          "Find empty partition. Please ensure there is no empty"
                          " partition for spark dataframe",
                      )
  
      sqlContext = get_spark_sql_context(get_spark_context())
  
      batch_size = -1 if not batch_size else batch_size
      rdd_file = callZooFunc(
          "float", "sparkdfTopdf", df._jdf, sqlContext, batch_size
      )
      pd_rdd = rdd_file.mapPartitions(farrow)
      return pd_rdd
  
imports: from bigdl.dllib.utils.file_utils import get_file_list, callZooFunc
  from bigdl.dllib.utils.utils import convert_row_to_numpy
  from bigdl.dllib.utils.common import *
  from bigdl.dllib.utils.log4Error import *
  import pyspark.sql.functions
  from typing import TYPE_CHECKING, Dict, List, Optional, Type, Union
  from numpy import float32, int32
label_desc: Use image node_id 24 for calling a global function with example usage: to_pandas(df, squeeze, index_col, dtype, index_map, batch_size) and returns: pd_rdd