using PositiveIntegers

Author: fchapoton

src/sage/modular/multiple_zeta.py

@@ -191,8 +191,7 @@
 from sage.modules.free_module import VectorSpace
 from sage.rings.integer_ring import ZZ
 from sage.rings.rational_field import QQ
-from sage.sets.integer_range import IntegerRange
-from sage.rings.infinity import Infinity
+from sage.sets.positive_integers import PositiveIntegers
 
 # multiplicative generators for weight <= 17
 # using the following convention
@@ -661,10 +660,8 @@ def __init__(self, R):
         cat = GradedAlgebrasWithBasis(R).Commutative()
         if R in Domains():
             cat = cat & Domains()
-        NN1 = IntegerRange(1, Infinity)
-        CombinatorialFreeModule.__init__(self, R, Words(NN1, infinite=False),
-                                         prefix="Z",
-                                         category=cat)
+        W = Words(PositiveIntegers(), infinite=False)
+        CombinatorialFreeModule.__init__(self, R, W, prefix="Z", category=cat)
 
     def _repr_(self):
         r"""