missing import

Author: Jonathan Kliem

src/sage/geometry/polyhedron/backend_ppl.py

@@ -6,13 +6,15 @@
 from sage.rings.integer import Integer
 from sage.arith.functions import LCM_list
 from sage.misc.functional import denominator
+from .base import Polyhedron_base
+from .base_QQ import Polyhedron_QQ
+from .base_ZZ import Polyhedron_ZZ
+
+from sage.misc.lazy_import import lazy_import
 from sage.features import PythonModule
 lazy_import('ppl', ['C_Polyhedron', 'Generator_System', 'Constraint_System',
                     'Linear_Expression', 'line', 'ray', 'point'],
                     feature=PythonModule("ppl", spkg="pplpy"))
-from .base import Polyhedron_base
-from .base_QQ import Polyhedron_QQ
-from .base_ZZ import Polyhedron_ZZ
 
 
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