src/sage/rings/continued_fraction.py: Use sage.rings.abc

sagemath · Oct 23, 2021 · fbf6666 · fbf6666
1 parent 7e8f0bb
commit fbf6666
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/src/sage/rings/continued_fraction.py b/src/sage/rings/continued_fraction.py
@@ -2451,12 +2451,11 @@ def continued_fraction_list(x, type="std", partial_convergents=False,
 
     cf = None
 
-    from sage.rings.real_arb import RealBallField
-    from sage.rings.real_mpfi import RealIntervalField, RealIntervalField_class
     from sage.rings.real_mpfr import RealLiteral
     if isinstance(x, RealLiteral):
+        from sage.rings.real_mpfi import RealIntervalField
         x = RealIntervalField(x.prec())(x)
-    if isinstance(x.parent(), (RealIntervalField_class, RealBallField)):
+    if isinstance(x.parent(), (sage.rings.abc.RealIntervalField, sage.rings.abc.RealBallField)):
         cf = continued_fraction(rat_interval_cf_list(
                  x.lower().exact_rational(),
                  x.upper().exact_rational()))
@@ -2658,8 +2657,8 @@ def continued_fraction(x, value=None):
     except AttributeError:
         pass
 
-    from .real_mpfi import RealIntervalField
     if is_real is False:
+        from .real_mpfi import RealIntervalField
         # we cannot rely on the answer of .is_real() for elements of the
         # symbolic ring. The thing below is a dirty temporary hack.
         RIF = RealIntervalField(53)