Allow schema encoding (auto-)escapes

implementations/python/preserves/schema.py

@@ -279,7 +279,15 @@ class Definition(SchemaObject):
     def __setitem__(self, name, value):
         return safesetattr(self, name, value)
 
+class escape:
+    def __init__(self, escaped):
+        self.escaped = escaped
+    def __escape_schema__(self):
+        return self.escaped
+
 def encode(p, v):
+    if hasattr(v, '__escape_schema__'):
+        return preserve(v.__escape_schema__())
     if p == ANY:
         return v
     if p.key == NAMED: