1"""
2Common utilities for testing model selection.
3"""
4
5import numpy as np
6
7from sklearn.model_selection import KFold
8
9
10class OneTimeSplitter:
11    """A wrapper to make KFold single entry cv iterator"""
12
13    def __init__(self, n_splits=4, n_samples=99):
14        self.n_splits = n_splits
15        self.n_samples = n_samples
16        self.indices = iter(KFold(n_splits=n_splits).split(np.ones(n_samples)))
17
18    def split(self, X=None, y=None, groups=None):
19        """Split can be called only once"""
20        for index in self.indices:
21            yield index
22
23    def get_n_splits(self, X=None, y=None, groups=None):
24        return self.n_splits
25