diff --git a/accountant/views/accounts.py b/accountant/views/accounts.py
index 46a4c4d..44eddbb 100644
--- a/accountant/views/accounts.py
+++ b/accountant/views/accounts.py
@@ -149,10 +149,7 @@ class AccountListResource(Resource):
 
         # A new account MUST NOT have an id;
         if 'id' in data and data['id']:
-            ns.abort(
-                406,
-                error_message='Id must not be provided on creation.'
-            )
+            ns.abort(406, 'Id must not be provided on creation.')
 
         # Instantiate account with data.
         account = Account(**data)
@@ -189,10 +186,7 @@ class AccountResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         # Note: if we don't pass the code, the result is seen as a tuple and
         # causes error on marshalling.
@@ -210,19 +204,13 @@ class AccountResource(Resource):
 
         # Check ID consistency.
         if 'id' in data and data['id'] and data['id'] != account_id:
-            ns.abort(
-                406,
-                error_message='Id must not be provided or changed on update.'
-            )
+            ns.abort(406, 'Id must not be provided or changed on update.')
 
         # Need to get the object to update it.
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         # SQLAlchemy objects ignore __dict__.update() with merge.
         for k, v in data.items():
@@ -243,10 +231,7 @@ class AccountResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         db.session.delete(account)  # pylint: disable=no-member
 
@@ -275,10 +260,7 @@ class SoldsResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         # Note: if we don't pass the code, the result is seen as a tuple and
         # causes error on marshalling.
@@ -308,10 +290,7 @@ class BalanceResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         data = range_parser.parse_args()
 
diff --git a/accountant/views/operations.py b/accountant/views/operations.py
index a9a7fd8..d9c233c 100644
--- a/accountant/views/operations.py
+++ b/accountant/views/operations.py
@@ -129,17 +129,11 @@ class OperationListResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         # A new operation MUST NOT have an id;
         if 'id' in data and data['id']:
-            ns.abort(
-                406,
-                error_message='Id must not be provided on creation.'
-            )
+            ns.abort(406, 'Id must not be provided on creation.')
 
         operation = Operation(**data)
 
@@ -172,10 +166,7 @@ class OperationResource(Resource):
         # pylint: enable=no-member
 
         if not operation:
-            ns.abort(
-                404,
-                error_message='Operation with id %d not found.' % operation_id
-            )
+            ns.abort(404, 'Operation with id %d not found.' % operation_id)
 
         return operation, 200
 
@@ -191,20 +182,14 @@ class OperationResource(Resource):
 
         # Check ID consistency.
         if 'id' in data and data['id'] and data['id'] != operation_id:
-            ns.abort(
-                406,
-                error_message='Id must not be provided or changed on update.'
-            )
+            ns.abort(406, 'Id must not be provided or changed on update.')
 
         # pylint: disable=no-member
         operation = db.session.query(Operation).get(operation_id)
         # pylint: enable=no-member
 
         if not operation:
-            ns.abort(
-                404,
-                error_message='Operation with id %d not found.' % operation_id
-            )
+            ns.abort(404, 'Operation with id %d not found.' % operation_id)
 
         # FIXME check account_id consistency.
 
@@ -227,10 +212,7 @@ class OperationResource(Resource):
         # pylint: enable=no-member
 
         if not operation:
-            ns.abort(
-                404,
-                error_message='Operation with id %d not found.' % operation_id
-            )
+            ns.abort(404, 'Operation with id %d not found.' % operation_id)
 
         db.session.delete(operation)  # pylint: disable=no-member
 
diff --git a/accountant/views/scheduled_operations.py b/accountant/views/scheduled_operations.py
index 7e9ce90..c393495 100644
--- a/accountant/views/scheduled_operations.py
+++ b/accountant/views/scheduled_operations.py
@@ -103,17 +103,11 @@ class ScheduledOperationListResource(Resource):
         account = Account.query().get(account_id)
 
         if not account:
-            ns.abort(
-                404,
-                error_message='Account with id %d not found.' % account_id
-            )
+            ns.abort(404, 'Account with id %d not found.' % account_id)
 
         # A new scheduled operation MUST NOT have an id;
         if 'id' in data and data['id']:
-            ns.abort(
-                406,
-                error_message='Id must not be provided on creation.'
-            )
+            ns.abort(406, 'Id must not be provided on creation.')
 
         scheduled_operation = ScheduledOperation(**data)
 
@@ -150,10 +144,7 @@ class ScheduledOperationResource(Resource):
         scheduled_operation = ScheduledOperation.query().get(so_id)
 
         if not scheduled_operation:
-            ns.abort(
-                404,
-                error_message='Scheduled operation with id %d not found.' % so_id
-            )
+            ns.abort(404, 'Scheduled operation with id %d not found.' % so_id)
 
         return scheduled_operation, 200
 
@@ -170,18 +161,12 @@ class ScheduledOperationResource(Resource):
 
         # Check ID consistency.
         if 'id' in data and data['id'] and data['id'] != so_id:
-            ns.abort(
-                406,
-                error_message='Id must not be provided or changed on update.'
-            )
+            ns.abort(406, 'Id must not be provided or changed on update.')
 
         scheduled_operation = ScheduledOperation.query().get(so_id)
 
         if not scheduled_operation:
-            ns.abort(
-                404,
-                error_message='Scheduled operation with id %d not found.' % so_id
-            )
+            ns.abort(404, 'Scheduled operation with id %d not found.' % so_id)
 
         # FIXME check account_id consistency.
 
@@ -209,20 +194,15 @@ class ScheduledOperationResource(Resource):
         scheduled_operation = ScheduledOperation.query().get(so_id)
 
         if not scheduled_operation:
-            ns.abort(
-                404,
-                error_message='Scheduled operation with id %d not found.' % so_id
-            )
+            ns.abort(404, 'Scheduled operation with id %d not found.' % so_id)
 
         operations = scheduled_operation.operations.filter(
             Operation.confirmed == true()
         ).count()
 
         if operations:
-            ns.abort(
-                409,
-                error_message='There are still confirmed operations \
-                associated to this scheduled operation.')
+            ns.abort(409, 'There are still confirmed operations '
+                     'associated to this scheduled operation.')
 
         # Delete unconfirmed operations
         scheduled_operation.operations.delete()
diff --git a/accountant/views/users.py b/accountant/views/users.py
index 5088eb7..868aa81 100644
--- a/accountant/views/users.py
+++ b/accountant/views/users.py
@@ -72,7 +72,7 @@ class LoginResource(Resource):
         ).one_or_none()
 
         if not user or not user.verify_password(password):
-            ns.abort(401, error_message="Bad user or password.")
+            ns.abort(401, "Bad user or password.")
 
         return {
             'access_token': create_access_token(identity=user),