chore: import upstream snapshot with attribution

rllib/examples/multi_agent/utils/__init__.py

@@ -0,0 +1,43 @@
+import sys
+
+from ray.rllib.examples.multi_agent.utils.self_play_callback import SelfPlayCallback
+from ray.rllib.examples.multi_agent.utils.self_play_callback_old_api_stack import (
+    SelfPlayCallbackOldAPIStack,
+)
+from ray.rllib.examples.multi_agent.utils.self_play_league_based_callback import (
+    SelfPlayLeagueBasedCallback,
+)
+from ray.rllib.examples.multi_agent.utils.self_play_league_based_callback_old_api_stack import (  # noqa
+    SelfPlayLeagueBasedCallbackOldAPIStack,
+)
+
+
+def ask_user_for_action(time_step):
+    """Asks the user for a valid action on the command line and returns it.
+
+    Re-queries the user until she picks a valid one.
+
+    Args:
+        time_step: The open spiel Environment time-step object.
+    """
+    pid = time_step.observations["current_player"]
+    legal_moves = time_step.observations["legal_actions"][pid]
+    choice = -1
+    while choice not in legal_moves:
+        print("Choose an action from {}:".format(legal_moves))
+        sys.stdout.flush()
+        choice_str = input()
+        try:
+            choice = int(choice_str)
+        except ValueError:
+            continue
+    return choice
+
+
+__all__ = [
+    "ask_user_for_action",
+    "SelfPlayCallback",
+    "SelfPlayLeagueBasedCallback",
+    "SelfPlayCallbackOldAPIStack",
+    "SelfPlayLeagueBasedCallbackOldAPIStack",
+]