'Construct an element of `self` domain from `a`.'

def new(self, a):

    res = self.dtype(a, self.dom, (len(self.gens) - 1), ring=self)
    if (res.denom().terms(order=self.order)[0][0] != ((0,) * len(self.gens))):
        from sympy.printing.str import sstr
        raise CoercionFailed(('denominator    %s    not    allowed    in    %s' % (sstr(res), self)))
    return res
