improving ImportError for Box2D

gymnasium/envs/box2d/bipedal_walker.py

@@ -23,7 +23,7 @@
     )
 except ImportError as e:
     raise DependencyNotInstalled(
-        'Box2D is not installed, run `pip install "gymnasium[box2d]"`'
+        'Box2D is not installed, you can install it by run `pip install swig` followed by `pip install "gymnasium[box2d]"`'
     ) from e
 
 

gymnasium/envs/box2d/car_dynamics.py

@@ -19,7 +19,7 @@
     from Box2D.b2 import fixtureDef, polygonShape, revoluteJointDef
 except ImportError as e:
     raise DependencyNotInstalled(
-        'Box2D is not installed, run `pip install "gymnasium[box2d]"`'
+        'Box2D is not installed, you can install it by run `pip install swig` followed by `pip install "gymnasium[box2d]"`'
     ) from e
 
 

gymnasium/envs/box2d/car_racing.py

@@ -17,7 +17,7 @@
     from Box2D.b2 import contactListener, fixtureDef, polygonShape
 except ImportError as e:
     raise DependencyNotInstalled(
-        'Box2D is not installed, run `pip install "gymnasium[box2d]"`'
+        'Box2D is not installed, you can install it by run `pip install swig` followed by `pip install "gymnasium[box2d]"`'
     ) from e
 
 try:

gymnasium/envs/box2d/lunar_lander.py

@@ -24,7 +24,7 @@
     )
 except ImportError as e:
     raise DependencyNotInstalled(
-        'Box2D is not installed, run `pip install "gymnasium[box2d]"`'
+        'Box2D is not installed, you can install it by run `pip install swig` followed by `pip install "gymnasium[box2d]"`'
     ) from e