diff --git a/bijoe/schemas.py b/bijoe/schemas.py
index 1f4bc8b..ec7b8dd 100644
--- a/bijoe/schemas.py
+++ b/bijoe/schemas.py
@@ -167,20 +167,19 @@ class Dimension(Base):
         'absent_label': six.text_type,
     }
 
-    label = None
-    value_label = None
-    order_by = None
-    group_by = None
-    join = None
-    filter = True
-    filter_in_join = False
-    filter_value = None
-    filter_expression = None
-    filter_needs_join = True
-    members_query = None
-    absent_label = None
-
     def __init__(self, **kwargs):
+        self.label = None
+        self.value_label = None
+        self.order_by = None
+        self.group_by = None
+        self.join = None
+        self.filter = True
+        self.filter_in_join = False
+        self.filter_value = None
+        self.filter_expression = None
+        self.filter_needs_join = True
+        self.members_query = None
+        self.absent_label = None
         super(Dimension, self).__init__(**kwargs)
         if not self.absent_label:
             if self.type in ('date', 'integer', 'string'):
@@ -345,7 +344,9 @@ class Join(Base):
         'kind': join_kind,
     }
 
-    kind = 'full'
+    def __init__(self, **kwargs):
+        self.kind = 'full'
+        super(Join, self).__init__(**kwargs)
 
     @property
     def master_table(self):
@@ -369,11 +370,13 @@ class Cube(Base):
         'warnings': [six.text_type],
     }
 
-    json_field = None
-    joins = ()
-    dimensions = ()
-    measures = ()
-    warnings = ()
+    def __init__(self, **kwargs):
+        self.json_field = None
+        self.joins = ()
+        self.dimensions = ()
+        self.measures = ()
+        self.warnings = ()
+        super(Cube, self).__init__(**kwargs)
 
     def check(self):
         names = collections.Counter()
@@ -423,8 +426,10 @@ class Warehouse(Base):
         'path': str,
     }
 
-    path = None
-    slug = None
+    def __init__(self, **kwargs):
+        self.path = None
+        self.slug = None
+        super(Warehouse, self).__init__(**kwargs)
 
     def check(self):
         names = collections.Counter(cube.name for cube in self.cubes)