e sparse. Note that large sparse matrices and arrays
    requiring `int64` indices are not accepted.

y : array-like of shape (n_samples,)
    Target values.

sample_weight : float or array-like of shape (n_samples,),                 default=None
    Sample weights used for fitting and evaluation of the weighted
    mean squared error of each cv-fold. Note that the cross validated
    MSE that is finally used to find the best model is the unweighted
    mean over the (weighted) MSEs of each test fold.

**params : dict, default=None
    Parameters to be passed to the CV splitter.

    .. versionadded:: 1.4
        Only available if `enable_metadata_routing=True`,
        which can be set by using
        ``sklearn.set_config(enable_metadata_routing=True)``.
        See :ref:`Metadata Routing User Guide <metadata_routing>` for
        more details.

Returns
-------
self : object
    Returns an instance of fitted model.
rF