def pmul(self, a, b):
    ' product between two field element in Fp\n        '
    return FieldElem(((a.val * b.val) % self.p), self)
product between two field element in Fp
def pmul(self, a, b):
    ' \n        '
    return FieldElem(((a.val * b.val) % self.p), self)