Suppose i have a list of documents to insert say `lst`.
Now if i do `connection.database.collection.insert(lst)` it gives me error
`pymongo.errors.DuplicateKeyError: E11000 duplicate key error index: database.collection.$id`. So i have to explicitly pass `manipulate=False` to the insert function like this
`connection.database.collection.insert(lst, manipulate=False)`

This problem will also appear in case where i do
`
for doc in lst:
connection.database.collection.insert(doc)
`

So its better if we keep manipulate=True by default. In case somebody needs the inserted document id he should explicitly pass `manipulate=True`