'Returns the next imputed dataset in the imputation process.
Returns
data : array-like
An imputed dataset from the MICE chain.
Notes
`MICEData` does not have a `skip` parameter.  Consecutive
values returned by `next_sample` are immediately consecutive
in the imputation chain.
The returned value is a reference to the data attribute of
the class and should be copied before making any changes.'

def next_sample(self):

    self.update_all(1)
    return self.data
