def METHOD_NAME(
    self: T,
    fdata: FData,
    coefs: np.ndarray,
) -> Tuple[T, NDArrayFloat]:
    """
    Create a basis of the subspace generated by the given functions.
    Args:
        fdata: The resulting basis will span the subspace generated
            by these functions.
        coefs: Coefficients of some functions in the given fdata.
            These coefficients will be transformed into the coefficients
            of the same functions in the resulting basis.
    """
    raise ValueError(
        "Unexpected type of functional data object: {type}.".format(
            type=type(fdata),
        ),
    )