These changes are needed for two reasons.
**`__grouping_doc_end__` is in the wrong place**
If you look at the part of the Ray documentation where the tag is referenced, you'll read
> You can use the MultiAgentEnv.with_agent_groups() method to define these groups:
However, if you look at the code snippet below, you'll see the implementation of `to_base_env` in addition to the implementation of `with_agent_groups`.
To remove `to_base_env` from the code snippet, we need to move `__grouping_doc__end__`.
**Black cannot format `multi_agent_env.py`**
For some reason, Black errors while formatting `multi_agent_env.py`. However, if we move `__grouping_doc_end__` up, the issue is resolved.
* wip.
* Test: Make a change in tune to trigger tune tests, which are not run otherwise, but seem to fail nevertheless with this PR's changes.
* remove bare_metal_policy_with_custom_view_reqs from tests
* Remove all __future__ imports from RLlib.
* Remove (object) again from tf_run_builder.py::TFRunBuilder.
* Fix 2xLINT warnings.
* Fix broken appo_policy import (must be appo_tf_policy)
* Remove future imports from all other ray files (not just RLlib).
* Remove future imports from all other ray files (not just RLlib).
* Remove future import blocks that contain `unicode_literals` as well.
Revert appo_tf_policy.py to appo_policy.py (belongs to another PR).
* Add two empty lines before Schedule class.
* Put back __future__ imports into determine_tests_to_run.py. Fails otherwise on a py2/print related error.
