class_docstr: Lightweight immutable Dataframe similar to Pandas Dataframe.
class_docstr_tok: ["Lightweight","immutable","Dataframe","similar","to","Pandas","Dataframe","."]
code: def __str__(self) -> str:
      return (
          ",".join(self.column_names)
          + "\n"
          + "\n".join(
              ",".join("N/A" if v is None else str(v) for v in row)
              for row in self.rows
          )
      )
  
imports: import itertools
  import json
  from typing import Any, Callable, Optional, Sequence, Tuple, Union
  from collections import namedtuple
  import numpy
  from tensorflow.python.compiler.tensorrt.model_tests import model_handler
  import tensorflow.python.compiler.tensorrt.trt_convert
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 10 for calling the DataFrame obj's underlying member method code with example usage: obj.__str__() and returns: unknown