Backport PR #176: Fig bug: broken (dev) CLI command for adding a Sens…

…or (#176)

Accept either a generic_asset or a generic_asset_id when initializing a Sensor.

* Create draft PR for #175

* Allow passing a GenericAsset or an id

* Changelog entry

Co-authored-by: Flix6x <Flix6x@users.noreply.github.com>
Co-authored-by: F.N. Claessen <felix@seita.nl>

documentation/changelog.rst

@@ -24,6 +24,7 @@ New features
 Bugfixes
 -----------
 * Fix (dev) CLI command for adding a GenericAssetType [see `PR #173 <http://www.github.com/SeitaBV/flexmeasures/pull/173>`_]
+* Fix (dev) CLI command for adding a Sensor [see `PR #176 <http://www.github.com/SeitaBV/flexmeasures/pull/176>`_]
 
 Infrastructure / Support
 ----------------------

flexmeasures/data/models/time_series.py

@@ -39,10 +39,22 @@ class Sensor(db.Model, tb.SensorDBMixin):
         ),
     )
 
-    def __init__(self, name: str, generic_asset: GenericAsset, **kwargs):
+    def __init__(
+        self,
+        name: str,
+        generic_asset: Optional[GenericAsset] = None,
+        generic_asset_id: Optional[int] = None,
+        **kwargs,
+    ):
+        assert (generic_asset is None) ^ (
+            generic_asset_id is None
+        ), "Either generic_asset_id or generic_asset must be set."
         tb.SensorDBMixin.__init__(self, name, **kwargs)
         tb_utils.remove_class_init_kwargs(tb.SensorDBMixin, kwargs)
-        kwargs["generic_asset"] = generic_asset
+        if generic_asset is not None:
+            kwargs["generic_asset"] = generic_asset
+        else:
+            kwargs["generic_asset_id"] = generic_asset_id
         db.Model.__init__(self, **kwargs)
 
     @property