diff --git a/navitia_client/client/apis/contributors_apis.py b/navitia_client/client/apis/contributors_apis.py
index 1d886d3..5b1f210 100644
--- a/navitia_client/client/apis/contributors_apis.py
+++ b/navitia_client/client/apis/contributors_apis.py
@@ -10,15 +10,8 @@ def _get_contributors_from_response(
         raw_contributors_response: Any,
     ) -> Sequence[Contributor]:
         contributors = []
-        for contributor in raw_contributors_response:
-            contributors.append(
-                Contributor(
-                    id=contributor.get("id"),
-                    name=contributor.get("name"),
-                    license=contributor.get("license"),
-                    website=contributor.get("website"),
-                ),
-            )
+        for contributor_data in raw_contributors_response:
+            contributors.append(Contributor.from_json(contributor_data))
 
         return contributors
 
diff --git a/navitia_client/client/apis/coverage_apis.py b/navitia_client/client/apis/coverage_apis.py
index b9f206d..9589111 100644
--- a/navitia_client/client/apis/coverage_apis.py
+++ b/navitia_client/client/apis/coverage_apis.py
@@ -1,4 +1,3 @@
-from datetime import datetime
 from typing import Any, Sequence
 
 from navitia_client.client.apis.api_base_client import ApiBaseClient
@@ -9,33 +8,8 @@ class CoverageApiClient(ApiBaseClient):
     @staticmethod
     def _get_regions_from_response(raw_regions_response: Any) -> Sequence[Region]:
         regions = []
-        for region in raw_regions_response:
-            regions.append(
-                Region(
-                    id=region.get("id"),
-                    name=region.get("name"),
-                    dataset_created_at=datetime.fromisoformat(
-                        region.get("dataset_created_at")
-                    )
-                    if region.get("dataset_created_at")
-                    else None,
-                    end_production_date=datetime.strptime(
-                        region.get("end_production_date"), "%Y%m%d"
-                    )
-                    if region.get("end_production_date")
-                    else None,
-                    last_load_at=datetime.fromisoformat(region.get("last_load_at"))
-                    if region.get("last_load_at")
-                    else None,
-                    shape=region.get("shape"),
-                    start_production_date=datetime.strptime(
-                        region.get("start_production_date"), "%Y%m%d"
-                    )
-                    if region.get("end_production_date")
-                    else None,
-                    status=region.get("status"),
-                )
-            )
+        for region_data in raw_regions_response:
+            regions.append(Region.from_json(region_data))
         return regions
 
     def list_covered_areas(self) -> Sequence[Region]:
diff --git a/navitia_client/entities/administrative_region.py b/navitia_client/entities/administrative_region.py
index cf25f93..db54d55 100644
--- a/navitia_client/entities/administrative_region.py
+++ b/navitia_client/entities/administrative_region.py
@@ -14,6 +14,31 @@ class Region(BaseEntity):
     start_production_date: Optional[datetime]
     status: Optional[str]
 
+    @staticmethod
+    def from_json(payload: dict[str, Any]) -> "Region":
+        return Region(
+            id=payload["id"],
+            name=payload["name"],
+            dataset_created_at=datetime.fromisoformat(payload["dataset_created_at"])
+            if "dataset_created_at" in payload
+            else None,
+            end_production_date=datetime.strptime(
+                payload["end_production_date"], "%Y%m%d"
+            )
+            if "end_production_date" in payload
+            else None,
+            last_load_at=datetime.fromisoformat(payload["last_load_at"])
+            if "last_load_at" in payload
+            else None,
+            shape=payload["shape"],
+            start_production_date=datetime.strptime(
+                payload["start_production_date"], "%Y%m%d"
+            )
+            if "end_production_date" in payload
+            else None,
+            status=payload["status"],
+        )
+
 
 @dataclass
 class AdministrativeRegion(BaseEntity):
diff --git a/navitia_client/entities/contributor.py b/navitia_client/entities/contributor.py
index 0e8a6b0..c768eb1 100644
--- a/navitia_client/entities/contributor.py
+++ b/navitia_client/entities/contributor.py
@@ -1,5 +1,5 @@
 from dataclasses import dataclass
-from typing import Optional
+from typing import Any, Optional
 
 from navitia_client.entities.base_entity import BaseEntity
 
@@ -8,3 +8,12 @@
 class Contributor(BaseEntity):
     license: str
     website: Optional[str]
+
+    @staticmethod
+    def from_json(payload: dict[str, Any]) -> "Contributor":
+        return Contributor(
+            id=payload["id"],
+            name=payload["name"],
+            license=payload["license"],
+            website=payload["website"],
+        )
diff --git a/navitia_client/entities/dataset.py b/navitia_client/entities/dataset.py
index 6e46184..fc8fbe6 100644
--- a/navitia_client/entities/dataset.py
+++ b/navitia_client/entities/dataset.py
@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from datetime import datetime
-from typing import Optional
+from typing import Any, Optional
 
 from navitia_client.entities.contributor import Contributor
 
@@ -14,3 +14,19 @@ class Dataset:
     realtime_level: str
     start_validation_date: datetime
     system: Optional[str]
+
+    @staticmethod
+    def from_json(payload: dict[str, Any]) -> "Dataset":
+        return Dataset(
+            contributor=Contributor.from_json(payload["contributor"]),
+            description=payload["description"],
+            end_validation_date=datetime.strptime(
+                payload["end_validation_date"], "%Y%m%dT%H%M%S"
+            ),
+            id=payload["id"],
+            realtime_level=payload["realtime_level"],
+            start_validation_date=datetime.strptime(
+                payload["start_validation_date"], "%Y%m%dT%H%M%S"
+            ),
+            system=payload["system"],
+        )