Problem with types of container

[lesquoyb]

Describe the bug
In the documentation I've noticed that there's often some consistency problems with the types of containers, take for example the reverse operator:
One definition takes a container<KeyType,ValueType>) as input, but returns a container<unknown,unknown>. Both input and output should be exactly the same type. I think the types in the input come from java, hence the difference.
Another definition takes a map<K,V> as input and returns a map, in this case I don't know why we don't even have a map<unknown, unknown> as a return.

Expected behavior
A more uniform representation of types in the documentation of operators