make is_discrete/is_continuous strict

gym-unity/gym_unity/envs/__init__.py

                 else:
                     self._action_space = spaces.MultiDiscrete(branches)
 
-        else:
+        elif self.group_spec.action_spec.is_continuous():
+
+        else:
+            raise UnityGymException(
+                "The gym wrapper does not provide explicit support for both discrete "
+                "and continuous actions."
+            )
 
         # Set observations space
         list_spaces: List[gym.Space] = []

ml-agents-envs/mlagents_envs/base_env.py

         """
         Returns true if this Behavior uses discrete actions
         """
-        return self.discrete_size > 0
+        return self.discrete_size > 0 and self.continuous_size == 0
 
     # For backwards compatibility
     def is_continuous(self) -> bool:
-        return self.continuous_size > 0
+        return self.discrete_size == 0 and self.continuous_size > 0
 
     @property
     def discrete_branches(self) -> Tuple[int, ...]: