trying to get rid of some CommutativeRing

Author: fchapoton

src/sage/graphs/chrompoly.pyx

@@ -32,7 +32,7 @@ from memory_allocator cimport MemoryAllocator
 from sage.libs.gmp.mpz cimport *
 from sage.rings.integer_ring import ZZ
 from sage.rings.integer cimport Integer
-from sage.rings.ring cimport CommutativeRing
+from sage.structure.parent cimport Parent
 from sage.rings.polynomial.polynomial_integer_dense_flint cimport Polynomial_integer_dense_flint
 from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing
 
@@ -448,7 +448,7 @@ def chromatic_polynomial_with_cache(G, cache=None):
         sage: chromatic_polynomial_with_cache(G)
         x^2 - x
     """
-    cdef CommutativeRing R = PolynomialRing(ZZ, "x", implementation="FLINT")
+    cdef Parent R = PolynomialRing(ZZ, "x", implementation="FLINT")
     cdef Polynomial_integer_dense_flint one = R.one()
     cdef Polynomial_integer_dense_flint zero = R.zero()
     cdef Polynomial_integer_dense_flint x = R.gen()

src/sage/rings/derivation.py

@@ -62,7 +62,7 @@
     True
 
 Alternatively we can use the method
-:meth:`~sage.rings.ring.CommutativeRing.derivation`
+:meth:`~sage.categories.commutative_rings.CommutativeRings.ParentMethods.derivation`
 of the ring `A` to create derivations::
 
     sage: Dx = A.derivation(x); Dx