Create IVerifierStatus and add IVerifierStatus.ignored().

verification/base.py

Index: verification/base.py
diff --git a/verification/base.py b/verification/base.py
index c797c130c6b95d4e4706e1d79be9cb589c510889..e9178f11084217b62b1965a68cb6436821ca6411 100644
--- a/verification/base.py
+++ b/verification/base.py
@@ -44,8 +44,36 @@ class Verified(model.PersistentMixIn):
       return False
     return any(v.failed() for v in self.verifications.itervalues())
 
+  def ignored(self):
+    """This item shouldn't be processed any further.
 
-class SimpleStatus(model.PersistentMixIn):
+    At least one verification step marked it as ignored.
+    """
+    if not self.verifications:
+      return False
+    return any(v.ignored() for v in self.verifications.itervalues())
+
+  def done(self):
+    """Processing on this item is done."""
+    return self.ignored() or self.succeeded() or self.failed()
+
+
+class IVerifierStatus(model.PersistentMixIn):
+  """Interface for objects in Verified.verifications dictionary."""
+  def succeeded(self):
+    raise NotImplementedError()
+
+  def failed(self):
+    raise NotImplementedError()
+
+  def ignored(self):
+    raise NotImplementedError()
+
+  def done(self):
+    return self.ignored() or self.succeeded() or self.failed()
+
+
+class SimpleStatus(IVerifierStatus):
   """Base class to be used for simple true/false verifiers."""
   def __init__(self, state=None):
     super(SimpleStatus, self).__init__()
@@ -57,6 +85,9 @@ class SimpleStatus(model.PersistentMixIn):
   def failed(self):
     return self.state is False
 
+  def ignored(self):
+    return False
+
 
 class Verifier(object):
   name = None