ExperimentAxisQuery, AxisIndexer are explicitly ABCs

python-spec/src/somacore/query/query.py

@@ -1,3 +1,4 @@
+import abc
 from typing import (
     Any,
     Mapping,
@@ -39,7 +40,7 @@ class AxisColumnNames(TypedDict, total=False):
     """var columns to use. All columns if ``None`` or not present."""
 
 
-class ExperimentAxisQuery:
+class ExperimentAxisQuery(abc.ABC):
     """Axis-based query against a SOMA Experiment.
 
     ExperimentAxisQuery allows easy selection and extraction of data from a
@@ -254,7 +255,7 @@ def __exit__(self, *_: Any) -> None:
 """Things that can be converted to a NumPy array."""
 
 
-class AxisIndexer:
+class AxisIndexer(abc.ABC):
     """
     Given a query, provides index-building services for obs/var axis.