if you create a document with mongo like this :
db.test.insert({x:1, d: {a:1, b:2, c:3}})

db.test.find({d: {a:1, b:2, c:3}})
gives the document back.

now, if try to retrieve it in python :
db.test.find(dict(d=

{'a': 1, 'b': 2, 'c': 3}

))
I don't get any document.

it is ok when I "extend" the dict like this :
db.test.find(

{'d.a': 1, 'd.b': 2, 'd.c': 3}

)

I then tried again under mongo to change the order of the elements in the d array:
db.test.find({d: {a:1, c:3, b:2}})
gives no result.

Is it a bug or a feature to considerthat

{a: 1, b:2, c:3}

is different than

{a:1, c:3, b:2}

??

In python, they are equals...