[rllib] Fix to allow input strings that are not file paths (ray-proje…

…ct#16830)

rllib/train.py

@@ -182,10 +182,15 @@ def run(args, parser):
             inputs = force_list(input_)
             # This script runs in the ray/rllib dir.
             rllib_dir = Path(__file__).parent
-            abs_inputs = [
-                str(rllib_dir.absolute().joinpath(i))
-                if not os.path.exists(i) else i for i in inputs
-            ]
+
+            def patch_path(path):
+                if os.path.exists(path):
+                    return path
+                else:
+                    abs_path = str(rllib_dir.absolute().joinpath(path))
+                    return abs_path if os.path.exists(abs_path) else path
+
+            abs_inputs = list(map(patch_path, inputs))
             if not isinstance(input_, list):
                 abs_inputs = abs_inputs[0]