'Return a boolean indicating if namespace.name is defined.
:param namespace: The namespace that the property should be stored in.
:type namespace: string
:param name: The name the value was saved with.
:type name: string
:returns: True if the given name is defined in the given namespace and
False otherwise.
:rtype: bool'

@with_backing_file
def has(self, namespace, name):

    return ((namespace in self._state) and (name in self._state[namespace]))
