error properly when a keyword is not followed by a valid config in yaml

ml-agents/mlagents/trainers/learn.py

 def maybe_add_samplers(
     sampler_config: Optional[Dict], env: SubprocessEnvManager
 ) -> None:
-    restructured_sampler_config: Dict[str, List[float]] = {}
-        if "resampling-interval" in sampler_config:
-            logger.warning(
-                "The resampling-interval is no longer necessary for parameter randomization. It is being ignored."
-            )
-            sampler_config.pop("resampling-interval")
-        for param, config in sampler_config.items():
-            restructured_sampler_config[param] = config
-        env.reset(config=restructured_sampler_config)
+        env.reset(config=sampler_config)
 
 
 def try_create_meta_curriculum(

ml-agents/mlagents/trainers/settings.py

 from mlagents.trainers.exception import TrainerConfigError
 from mlagents.trainers.models import ScheduleType, EncoderType
 
+from mlagents_envs import logging_util
+
+logger = logging_util.get_logger(__name__)
+
 
 def check_and_structure(key: str, value: Any, class_type: type) -> Any:
     attr_fields_dict = attr.fields_dict(class_type)
             )
         d_final: Dict[str, List[float]] = {}
         for param, param_config in d.items():
+            if param == "resampling-interval":
+                logger.warning(
+                    "The resampling-interval is no longer necessary for parameter randomization. It is being ignored."
+                )
+                continue
+            if not isinstance(param_config, Mapping):
+                raise TrainerConfigError(
+                    f"Unsupported distribution configuration {param_config}."
+                )
             for key, val in param_config.items():
                 enum_key = ParameterRandomizationType(key)
                 t = enum_key.to_settings()