def _feature_wrapper(f):
    """Wrapper for feature optimization.

    This is a wrapper for use with multi-threaded versions.
    Unfortunately Python threads are *terrible*, so this doesn't
    actually get used.

    Parameters
    ------
     f : list
         Array of inputs. f[0] is the name of the feature. f[1]
         is the feature object itself. f[2] is N * fpumz (the
         vector input to the feature during optimization). f[3]
         is the ADMM parameter, rho.

    Returns
    -------
     name : str
         The name of the feature. (The same as the input.)
     f_j : array
         The array of fitted values returned by the feature.
    """

    return f[0], f[1].optimize(f[2], f[3])