src/sage/schemes/projective/projective_morphism.py: Use sage.rings.abc

sagemath · Oct 23, 2021 · 6dce213 · 6dce213
1 parent f3dd7cc
commit 6dce213
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/sage/schemes/projective/projective_morphism.py b/src/sage/schemes/projective/projective_morphism.py
@@ -74,6 +74,7 @@
 
 from sage.calculus.functions import jacobian
 
+import sage.rings.abc
 from sage.rings.all import Integer
 from sage.rings.algebraic_closure_finite_field import AlgebraicClosureFiniteField_generic
 from sage.rings.complex_mpfr import ComplexField_class
@@ -1605,7 +1606,8 @@ def rational_preimages(self, Q, k=1):
             raise TypeError("must be an endomorphism of projective space")
         if not Q in self.codomain():
             raise TypeError("point must be in codomain of self")
-        if isinstance(BR.base_ring(),(ComplexField_class, RealField_class,RealIntervalField_class, ComplexIntervalField_class)):
+        if isinstance(BR.base_ring(), (sage.rings.abc.ComplexField, sage.rings.abc.RealField,
+                                       sage.rings.abc.RealIntervalField, sage.rings.abc.ComplexIntervalField)):
             raise NotImplementedError("not implemented over precision fields")
         PS = self.domain().ambient_space()
         N = PS.dimension_relative()