In JS/Node SDK, both form of document path are accepted: ``` document="/messages/{messageId}" document="messages/{messageId}" ``` This is done by normalizing document path ([code](https://github.com/firebase/firebase-functions/blob/47cfc61b52448e711af9261722049af58471b545/src/common/utilities/path.ts#L6-L11)). This "magic" is missing in the python sdk.
