cleanup

python/ipnb/src/org/jetbrains/plugins/ipnb/psi/IpnbPyFragment.java

@@ -49,12 +49,14 @@ public class IpnbPyFragment extends PyFileImpl {
     return clone;
   }
 
+  @Override
   @NotNull
   public FileViewProvider getViewProvider() {
     if (myViewProvider != null) return myViewProvider;
     return super.getViewProvider();
   }
 
+  @Override
   public boolean isPhysical() {
     return myPhysical;
   }

python/src/com/jetbrains/python/psi/impl/PyExpressionCodeFragmentImpl.java

@@ -59,12 +59,14 @@ public class PyExpressionCodeFragmentImpl extends PyFileImpl implements PyExpres
     return myContext != null && myContext.isValid() ? myContext : super.getContext();
   }
 
+  @Override
   @NotNull
   public FileViewProvider getViewProvider() {
     if(myViewProvider != null) return myViewProvider;
     return super.getViewProvider();
   }
 
+  @Override
   public boolean isPhysical() {
     return myPhysical;
   }

python/src/com/jetbrains/python/psi/impl/PyListLiteralExpressionImpl.java

@@ -50,12 +50,14 @@ public class PyListLiteralExpressionImpl extends PySequenceExpressionImpl implem
     }
   }
 
+  @Override
   public PsiElement addAfter(@NotNull PsiElement psiElement, PsiElement afterThis) throws IncorrectOperationException {
     checkPyExpression(psiElement);
     checkPyExpression(afterThis);
     return PyElementGenerator.getInstance(getProject()).insertItemIntoList(this, (PyExpression)afterThis, (PyExpression)psiElement);
   }
 
+  @Override
   public PsiElement addBefore(@NotNull PsiElement psiElement, PsiElement beforeThis) throws IncorrectOperationException {
     checkPyExpression(psiElement);
     return PyElementGenerator.getInstance(getProject()).insertItemIntoList(this, null, (PyExpression)psiElement);