trac #15333 remove global imports in structure/all.py

Author: Frédéric Chapoton

src/sage/structure/all.py

@@ -7,39 +7,18 @@
 from sage_object   import SageObject
 
 from element import (\
-    is_AdditiveGroupElement,
-    is_AlgebraElement,
-    is_CommutativeAlgebraElement,
-    is_CommutativeRingElement,
-    is_DedekindDomainElement,
-    is_EuclideanDomainElement,
-    is_FieldElement,
-    is_InfinityElement,
-    is_IntegralDomainElement,
-    is_Element,
-    is_Matrix,
-    is_MonoidElement,
-    is_ModuleElement,
-    is_MultiplicativeGroupElement,
-    is_PrincipalIdealDomainElement,
-    is_RingElement,
-    is_Vector,
-
     canonical_coercion,
     get_coercion_model,
     coercion_traceback
     )
 
-from parent      import Parent, is_Parent
+from parent      import Parent
 
-from parent_base import ParentWithBase, is_ParentWithBase
+from parent_base import ParentWithBase
 
 from parent_gens import (ParentWithGens,
-                         is_ParentWithGens,
                          ParentWithAdditiveAbelianGens,
-                         is_ParentWithAdditiveAbelianGens,
                          ParentWithMultiplicativeAbelianGens,
-                         is_ParentWithMultiplicativeAbelianGens,
                          localvars)
 
 import proof.all as proof