class_docstr: Abstract base class for all data formatters.
  
  User can implement the abstract methods below to perform dataset-specific
  manipulations.
class_docstr_tok: ["Abstract","base","class","for","all","data","formatters",".","User","can","implement","the","abstract","methods","below","to","perform","dataset-specific","manipulations","."]
docstr: Defines order, input type and data type of each column.
docstr_tok: ["Defines","order",",","input","type","and","data","type","of","each","column","."]
code: def _column_definition(self):
      """Defines order, input type and data type of each column."""
      raise NotImplementedError()
  
file_path: qlib/examples/benchmarks/TFT/data_formatters/base.py
imports: import abc
  import enum
label_desc: Use image node_id 5 for calling the GenericDataFormatter obj's underlying member method code with example usage: obj._column_definition() without return types