'Adds additional checking to make sure handler has correct fields.
In addition to normal ValidatedCheck calls GetHandlerType
which validates all the handler fields are configured
properly.
Raises:
UnknownHandlerType: when none of the no handler id attributes are set.
UnexpectedHandlerAttribute: when an unexpected attribute is set for the
discovered handler type.
HandlerTypeMissingAttribute: when the handler is missing a required
attribute for its handler type.
ContentTypeSpecifiedMultipleTimes: when mime_type is inconsistent with
http_headers.'

def CheckInitialized(self):

    super(URLMap, self).CheckInitialized()
    if (self.GetHandlerType() in (STATIC_DIR, STATIC_FILES)):
        self.AssertUniqueContentType()
