class_docstr: Python interface for VegaFusion DataFrame
docstr: See: https://vega.github.io/vega/docs/transforms/fold/
  
  :param fields: List of fields to fold
  :param value_col: Name of output value column
  :param key_col: Name of output key column
  :param order_field: Name of input ordering column or
      None if input ordering is not defined
  :return: DataFrameDataset
docstr_tok: ["See",":","https",":","\/\/vega.github.io\/vega\/docs\/transforms\/fold\/",":","param","fields",":","List","of","fields","to","fold",":","param","value_col",":","Name","of","output","value","column",":","param","key_col",":","Name","of","output","key","column",":","param","order_field",":","Name","of","input","ordering","column","or","None","if","input","ordering","is","not","defined",":","return",":","DataFrameDataset"]
code: def fold(
      self,
      fields: List[str],
      value_col: str,
      key_col: str,
      order_field: Optional[str],
  ) -> "DataFrameDataset":
      """
      See: https://vega.github.io/vega/docs/transforms/fold/
  
      :param fields: List of fields to fold
      :param value_col: Name of output value column
      :param key_col: Name of output key column
      :param order_field: Name of input ordering column or
          None if input ordering is not defined
      :return: DataFrameDataset
      """
      raise DataFrameOperationNotSupportedError()
  
imports: from abc import ABC, abstractmethod
  import pyarrow
  from vegafusion.proto.datafusion_pb2 import LogicalExprNode
  from typing import Optional, List, Literal, Union, Any
label_desc: Use image node_id 11 for calling the DataFrameDataset obj's underlying member method code with example usage: obj.fold(fields, value_col, key_col, order_field) without return types