>>> from congruents import congruent_nums
>>> from fractions import Fraction

---ini-ex

>>> l = [Fraction(1, 3), Fraction(3, 3), Fraction(4, 3), Fraction(2, 6)]
>>> l.extend([Fraction(14, 6), Fraction(5, 3), Fraction(-2, 3), Fraction(-22, 6)])
>>> it1, it2 = congruent_nums(iter(l), Fraction(1, 3))
>>> it1 == iter(it1) and list(it1) == [1, 4, 1, 7] and  it2 == iter(it2) and list(it2) == [-2, -11]
True

---fi-ex