Fix for #2949.

Extend the set of types that are not handled by json.dumps to elementary types.

Author: Christian Osendorfer

src/sagemaker/estimator.py

@@ -598,7 +598,9 @@ def _json_encode_hyperparameters(hyperparameters: Dict[str, Any]) -> Dict[str, A
         current_hyperparameters = hyperparameters
         if current_hyperparameters is not None:
             hyperparameters = {
-                str(k): (v if isinstance(v, (Parameter, Expression, Properties)) else json.dumps(v))
+               str(k): (v if isinstance(
+                    v, (str, int, float, bool, Parameter, Expression, Properties)
+                    ) else json.dumps(v))
                 for (k, v) in current_hyperparameters.items()
             }
         return hyperparameters