class_docstr: Keys we can group by. 
class_docstr_tok: ["Keys","we","can","group","by","."]
docstr: Type/class of the data of this key. 
docstr_tok: ["Type\/class","of","the","data","of","this","key","."]
code: def key_type(self) -> Type[Any]:
      """Type/class of the data of this key."""
      return self.value[1]
  
imports: import heapq
  from dataclasses import dataclass
  from enum import Enum
  from typing import Any, Collection, Iterator, List, Sequence, Tuple, Type
  import pandas
  from benchmark.metadata import BenchmarkMetadata
  from benchmark.plotter_api import Plotter
label_desc: Use image node_id 3 for calling the GroupingKey obj's underlying member method code with example usage: obj.key_type() and returns: self