Let single-component spaces not use Tuple Spaces

src/primaite/environment/observations.py

@@ -1,7 +1,7 @@
 """Module for handling configurable observation spaces in PrimAITE."""
 import logging
 from abc import ABC, abstractmethod
-from typing import TYPE_CHECKING, List, Tuple
+from typing import TYPE_CHECKING, List, Tuple, Union
 
 import numpy as np
 from gym import spaces
@@ -278,7 +278,7 @@ class ObservationsHandler:
         """Initialise the handler without any components yet. They"""
         self.registered_obs_components: List[AbstractObservationComponent] = []
         self.space: spaces.Space
-        self.current_observation: Tuple[np.ndarray]
+        self.current_observation: Union[Tuple[np.ndarray], np.ndarray]
         # i can access the registry items like this:
         # self.registry.LINK_TRAFFIC_LEVELS
 
@@ -288,6 +288,11 @@ class ObservationsHandler:
         for obs in self.registered_obs_components:
             obs.update()
             current_obs.append(obs.current_observation)
+
+        # If there is only one component, don't use a tuple, just pass through that component's obs.
+        if len(current_obs) == 1:
+            self.current_observation = current_obs[0]
+        else:
             self.current_observation = tuple(current_obs)
 
     def register(self, obs_component: AbstractObservationComponent):
@@ -305,6 +310,11 @@ class ObservationsHandler:
         component_spaces = []
         for obs_comp in self.registered_obs_components:
             component_spaces.append(obs_comp.space)
+
+        # If there is only one component, don't use a tuple space, just pass through that component's space.
+        if len(component_spaces) == 1:
+            self.space = component_spaces[0]
+        else:
             self.space = spaces.Tuple(component_spaces)
 
     @classmethod