remove asserts

sympy/polys/polytools.py

@@ -4052,19 +4052,11 @@ def cancel(f, g, include=False):
             cq = dom.to_sympy(cq)
 
             c, n, d =  cp/cq, per(p), per(q)
-            if c.is_Integer:
-                if n.domain == QQ:
-                    n, d = map(per, [i.convert(ZZ) for i in (p, q)])
-            elif c.is_Rational and n.domain == ZZ:
-                assert None
-                n, d = map(per, [i.convert(QQ) for i in (p, q)])
+            if c.is_Integer and n.domain == QQ:
+                n, d = map(per, [i.convert(ZZ) for i in (p, q)])
             return c, n, d
         else:
-            n, d = map(per, result)
-            if n.domain == QQ and any(i.dom == ZZ for i in result):
-                assert None
-                n, d = map(per, [i.convert(ZZ) for i in result])
-            return n, d
+            return tuple(map(per, result))
 
     def make_monic_over_integers_by_scaling_roots(f):
         """