Version 0.4.0 breaks compatibility with 0.3.0.
There was a large number of unorganized methods that made usage of the library difficult. In 0.4.0 the methods are organized into functionality groups. Each group is prefixed with `g_`. The group names mimics `cardano-cli`.
For example, instead of `cluster.get_tip()` we now have `cluster.g_query.get_tip()`.
There is a [sed script](https://github.com/input-output-hk/cardano-clusterlib-py/blob/v0.4.0/upgrading/refactor_to_0_4_0rc1.sed) that might help with refactoring to 0.4.0 methods organization.