class_docstr: A wrapper to make KFold single entry cv iterator
class_docstr_tok: ["A","wrapper","to","make","KFold","single","entry","cv","iterator"]
docstr: Split can be called only once
docstr_tok: ["Split","can","be","called","only","once"]
code: def split(self, X=None, y=None, groups=None):
      """Split can be called only once"""
      for index in self.indices:
          yield index
  
imports: import numpy
  from sklearn.model_selection import KFold
label_desc: Use image node_id 2 for calling the OneTimeSplitter obj's underlying member method code with example usage: obj.split(X, y, groups) without return types