cross_validation
          expanding_window_split(test_size, n_splits=5, step_size=1, eager=False)
  Return train/test splits using expanding window splitter.
Split time series repeatedly into an growing training set and a fixed-size test set.
For example, given test_size = 3, n_splits = 5 and step_size = 1,
the train os and test xs folds can be visualized as:
| o o o x x x - - - - |
| o o o o x x x - - - |
| o o o o o x x x - - |
| o o o o o o x x x - |
| o o o o o o o x x x |
Parameters:
| Name | Type | Description | Default | 
|---|---|---|---|
test_size | 
          
                int
           | 
          
             Number of test samples for each split.  | 
          required | 
n_splits | 
          
                int
           | 
          
             Number of splits.  | 
          
                5
           | 
        
step_size | 
          
                int
           | 
          
             Step size between windows.  | 
          
                1
           | 
        
eager | 
          
                bool
           | 
          
             If True return DataFrames. Otherwise, return LazyFrames.  | 
          
                False
           | 
        
Returns:
| Name | Type | Description | 
|---|---|---|
splitter |           
                Callable[LazyFrame, Mapping[int, Tuple[LazyFrame, LazyFrame]]]
           | 
          
             Function that takes a panel LazyFrame and Dict of (train, test) splits, where the key represents the split number (1,2,...,n_splits) and the value is a tuple of LazyFrames.  | 
        
          sliding_window_split(test_size, n_splits=5, step_size=1, window_size=10, eager=False)
  Return train/test splits using sliding window splitter.
Split time series repeatedly into a fixed-length training and test set.
For example, given test_size = 3, n_splits = 5, step_size = 1 and window_size=5
the train os and test xs folds can be visualized as:
| o o o o o x x x - - - - |
| - o o o o o x x x - - - |
| - - o o o o o x x x - - |
| - - - o o o o o x x x - |
| - - - - o o o o o x x x |
Parameters:
| Name | Type | Description | Default | 
|---|---|---|---|
test_size | 
          
                int
           | 
          
             Number of test samples for each split.  | 
          required | 
n_splits | 
          
                int
           | 
          
             Number of splits.  | 
          
                5
           | 
        
step_size | 
          
                int
           | 
          
             Step size between windows.  | 
          
                1
           | 
        
window_size | 
          
                int
           | 
          
             Window size for training.  | 
          
                10
           | 
        
eager | 
          
                bool
           | 
          
             If True return DataFrames. Otherwise, return LazyFrames.  | 
          
                False
           | 
        
Returns:
| Name | Type | Description | 
|---|---|---|
splitter |           
                Callable[LazyFrame, Mapping[int, Tuple[LazyFrame, LazyFrame]]]
           | 
          
             Function that takes a panel LazyFrame and Dict of (train, test) splits, where the key represents the split number (1,2,...,n_splits) and the value is a tuple of LazyFrames.  | 
        
          train_test_split(test_size, eager=False)
  Return a time-ordered train set and test set given test_size.
Parameters:
| Name | Type | Description | Default | 
|---|---|---|---|
test_size | 
          
                int
           | 
          
             Number of test samples.  | 
          required | 
eager | 
          
                bool
           | 
          
             If True, evaluate immediately and returns tuple of train-test   | 
          
                False
           | 
        
Returns:
| Name | Type | Description | 
|---|---|---|
splitter |           
                Callable[LazyFrame, Tuple[LazyFrame, LazyFrame]]
           | 
          
             Function that takes a panel LazyFrame and returns tuple of train / test LazyFrames.  |