'Generate a free module of rank ``rank`` over ``self``.
>>> from sympy.abc import x
>>> from sympy import QQ
>>> (QQ.old_poly_ring(x)/[x**2 + 1]).free_module(2)
(QQ[x]/<x**2 + 1>)**2'

def free_module(self, rank):

    return FreeModuleQuotientRing(self, rank)
