Support and-schemas in python

implementations/python/preserves/schema.py

@@ -132,7 +132,11 @@ class SchemaObject:
                 if k not in v: return None
                 if cls.parse(pp, v[k], args) is None: return None
             return ()
-        raise ValueError('Bad schema')
+        if p.key == AND:
+            for pp in p[0]:
+                if cls.parse(pp, v, args) is None: return None
+            return ()
+        raise ValueError(f'Bad schema {p}')
 
     def __preserve__(self):
         raise NotImplementedError('Subclass responsibility')