'method : LSDV, demeaned, MLE, GLS, BE, FE, optional
model :
between
fixed
random
pooled
[gmm]
effects :
oneway
time
twoway
femethod : demeaned (only one implemented)
WLS
remethod :
swar -
amemiya
nerlove
walhus
Notes
This is unfinished.  None of the method arguments work yet.
Only oneway effects should work.'

def fit(self, model=None, method=None, effects='oneway'):

    if method:
        method = method.lower()
    model = model.lower()
    if (method and (method not in ['lsdv', 'demeaned', 'mle', 'gls', 'be', 'fe'])):
        raise ValueError(('%s    not    a    valid    method' % method))
    if (model == 'pooled'):
        return GLS(self.endog, self.exog).fit()
    if (model == 'between'):
        return self._fit_btwn(method, effects)
    if (model == 'fixed'):
        return self._fit_fixed(method, effects)
