diff --git a/stac_model/examples.py b/stac_model/examples.py
index 79aaf41..fbc2ab8 100644
--- a/stac_model/examples.py
+++ b/stac_model/examples.py
@@ -1,8 +1,11 @@
+from datetime import datetime
+
 from stac_model.schema import (
     Asset,
     ClassObject,
     InputArray,
-    MLModelExtension,
+    MLModelHelper,
+    MLModelProperties,
     ModelInput,
     ModelOutput,
     ResultArray,
@@ -112,7 +115,7 @@ def eurosat_resnet():
         output_shape=[-1, 10],
         result_array=[result_array],
     )
-    ml_model_meta = MLModelExtension(
+    ml_model_meta = MLModelProperties(
         mlm_name="Resnet-18 Sentinel-2 ALL MOCO",
         mlm_task="classification",
         mlm_framework="pytorch",
@@ -129,4 +132,13 @@ def eurosat_resnet():
         mlm_runtime=[mlm_runtime],
         mlm_output=[mlm_output],
     )
-    return ml_model_meta
+
+    mlmodel_helper = MLModelHelper(attrs = ml_model_meta.model_dump())
+    geometry=None
+    bbox = [-90, -180, 90, 180]
+    start_time = datetime.strptime("1900-01-01", '%Y-%m-%d')
+    end_time = None
+    item = mlmodel_helper.stac_item(geometry, bbox, start_datetime=start_time,
+                                    end_datetime=end_time)
+
+    return item
diff --git a/stac_model/runtime.py b/stac_model/runtime.py
index 2872abf..ef78812 100644
--- a/stac_model/runtime.py
+++ b/stac_model/runtime.py
@@ -1,7 +1,7 @@
 from enum import Enum
 from typing import List, Optional
 
-from pydantic import BaseModel, ConfigDict, FilePath, field_validator
+from pydantic import AnyUrl, BaseModel, ConfigDict, FilePath
 
 from .paths import S3Path
 
@@ -11,7 +11,7 @@ class Asset(BaseModel):
     Follows the STAC Asset Object spec.
     """
 
-    href: S3Path | FilePath | str
+    href: S3Path | FilePath | AnyUrl| str
     title: Optional[str] = None
     description: Optional[str] = None
     type: Optional[str] = None
@@ -19,18 +19,6 @@ class Asset(BaseModel):
 
     model_config = ConfigDict(arbitrary_types_allowed = True)
 
-    @field_validator("href")
-    @classmethod
-    def check_path_type(cls, v):
-        if isinstance(v, str):
-            v = S3Path(url=v) if v.startswith("s3://") else FilePath(f=v)
-        else:
-            raise ValueError(
-                f"Expected str, S3Path, or FilePath input, received {type(v).__name__}"
-            )
-        return v
-
-
 class Container(BaseModel):
     container_file: str
     image_name: str
diff --git a/stac_model/schema.py b/stac_model/schema.py
index 1a60c30..115b66a 100644
--- a/stac_model/schema.py
+++ b/stac_model/schema.py
@@ -63,7 +63,6 @@ class MLModelProperties(BaseModel):
 class MLModelHelper:
     def __init__(self, attrs: MutableMapping[str, Any]):
         self.attrs = attrs
-        self.mlmodel_attrs = attrs["attributes"]
 
     @property
     def uid(self) -> str:
@@ -73,12 +72,12 @@ def uid(self) -> str:
             "mlm_task",
         ]
         name = "_".join("_".join(
-            self.mlmodel_attrs[k].split(" ")) for k in keys).lower()
+            self.attrs[k].split(" ")) for k in keys).lower()
         return name
 
     @property
     def properties(self) -> MLModelProperties:
-        props = MLModelProperties(**self.mlmodel_attrs)
+        props = MLModelProperties(**self.attrs)
         return props
 
     def stac_item(self, geometry: AnyGeometry, bbox: List[float],
diff --git a/tests/test_schema.py b/tests/test_schema.py
index 71359d2..cd3eb8a 100644
--- a/tests/test_schema.py
+++ b/tests/test_schema.py
@@ -5,10 +5,10 @@
 @pytest.fixture
 def metadata_json():
     from stac_model.examples import eurosat_resnet
-    model_metadata = eurosat_resnet()
-    return model_metadata.model_dump_json(indent=2)
+    model_metadata_stac_item = eurosat_resnet()
+    return model_metadata_stac_item
 
-def test_model_metadata_json_operations(metadata_json):
-    from stac_model.schema import MLModel
-    model_metadata = MLModel.model_validate_json(metadata_json)
+def test_model_metadata_json_operations(model_metadata_stac_item):
+    from stac_model.schema import MLModelExtension
+    model_metadata = MLModelExtension.apply(model_metadata_stac_item)
     assert model_metadata.mlm_name == "Resnet-18 Sentinel-2 ALL MOCO"