py2neo.neo4j.GraphDatabaseService.node(id) raise ClientError(e) - py2neo

Question

I think this might be an obvious to the seasoned py2neo users, but I could not get over it since I'm new. I'm trying to follow py2neo online doc: http://book.py2neo.org/en/latest/graphs_nodes_relationships/, but I was able to use the 'Node' methods for the instance returned from
GraphDatabaseService.create, but when I use GraphDatabaseService.node to retrieve the node, all the expected Node methods stop working, I've narrowed it down to an example below using the Node.len method.
Thanks in advance for any helpful insights.
Bruce
My env:
windows 7 professional
pycharm 3.4
py2neo 1.6.4
python2.7.5
Here are the codes:
from py2neo import node, neo4j
db = neo4j.GraphDatabaseService()
db.clear()
a, = db.create(node({'name': ['a']}))
a.add_labels('Label')
b = db.node(a._id)
print db.neo4j_version
print b, type(b)
print "There is %s node in db" % db.order
print len(b)
Here are the outputs:
C:\Python27\python.exe C:/Users/you_zhang/PycharmProjects/py2neo/ex11.py
(2, 0, 3, u'')
(10) <class 'py2neo.neo4j.Node'>
There is 1 node in db
Traceback (most recent call last):
File "C:/Users/you_zhang/PycharmProjects/py2neo/ex11.py", line 11, in <module>
print len(b)
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 1339, in __len__
return len(self.get_properties())
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 1398, in get_properties
self._properties = assembled(self._properties_resource._get()) or {}
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 1349, in _properties_resource
return self._subresource("properties")
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 403, in _subresource
uri = URI(self.__metadata__[key])
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 338, in __metadata__
self.refresh()
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 360, in refresh
self._metadata = ResourceMetadata(self._get().content)
File "C:\Users\you_zhang\AppData\Roaming\Python\Python27\site-packages\py2neo\neo4j.py", line 367, in _get
raise ClientError(e)
py2neo.exceptions.ClientError: Not Found

Answer 1

Your exact code snippet works for me (OS X, neo4j 2.1.2). There shouldn't be any problem. Have you tried to install the latest version of neo4j and run your code on a fresh and untouched database? I have encountered inconsistencies in corrupted databases.
Have you tried to load the node with .find()?
result = db.find('Label')
for n in result:
print(n)