docstr: List of columns that can be split on, i.e. that have more than one unique value
  
  Returns
  -------
  List[int]
      List of column numbers that can be split on
docstr_tok: ["List","of","columns","that","can","be","split","on",",","i.e",".","that","have","more","than","one","unique","value","Returns","--","--","--","-","List","[","int","]","List","of","column","numbers","that","can","be","split","on"]
code: def splittable_variables(self) -> List[int]:
      """
      List of columns that can be split on, i.e. that have more than one unique value
  
      Returns
      -------
      List[int]
          List of column numbers that can be split on
      """
      for i in range(0, self._n_features):
          if self._splittable_variables[i] is None:
              self._splittable_variables[i] = is_not_constant(
                  self.get_column(i)
              )
  
      return [
          i
          for (i, x) in enumerate(self._splittable_variables)
          if x is True
      ]
  
imports: from operator import gt, le
  from typing import Any, List, Optional, Union
  import numpy
  import pandas
  from .errors import NoSplittableVariableException
  from .splitcondition import SplitCondition
label_desc: Use image node_id 5 for calling the CovariateMatrix obj's underlying member method code with example usage: obj.splittable_variables() and returns: unknown