'Index can be a variable, variable name or an integer. Meta attributes
can be specified by negative indices or by indices above len(domain).'

def __getitem__(self, index):

    if (not isinstance(index, int)):
        index = self.domain.index(index)
    if (index < 0):
        index = (len(self.domain) + ((-1) - index))
    return self.stats[index]
