class_docstr: Python interface for VegaFusion DataFrame
docstr: DataFrame's pyarrow schema
docstr_tok: ["DataFrame","'s","pyarrow","schema"]
code: def schema(self) -> pa.Schema:
      """DataFrame's pyarrow schema"""
      raise NotImplementedError()
  
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 1 for calling the DataFrameDataset obj's underlying member method code with example usage: obj.schema() without return types