change subclass check for AbstractModelContainer

src/stpipe/container.py

@@ -16,39 +16,35 @@ class without requiring that they inherit this class.
     def __subclasshook__(cls, C):
         if cls is not AbstractModelContainer:
             return False
-        mro = C.__mro__
 
         # must provide "crds_observatory"
-        if not any(hasattr(CC, "crds_observatory") for CC in mro):
+        if not hasattr(C, "crds_observatory"):
             return False
 
         # and be iterable
-        if not any(hasattr(CC, "__iter__") for CC in mro):
+        if not hasattr(C, "__iter__"):
             return False
 
-        # and implement "save"
-        if not any(hasattr(CC, "save") for CC in mro):
-            return False
-
-        # and that "save" is a function
-        save_function = getattr(C, "save")
-        if not callable(save_function):
-            return False
-
-        # and that "save" accepts the required arguments/parameter
-        save_signature = inspect.signature(C.save)
-        target_signature = inspect.signature(cls.save)
-        for parameter in target_signature.parameters:
-            if parameter == "self":
-                pass
-            # check that this parameter/argument exists in the save function
-            if parameter not in save_signature.parameters:
-                return False
-            save_parameter = save_signature.parameters[parameter]
-            # make sure the required parameter is not positional only
-            if save_parameter.kind == inspect.Parameter.POSITIONAL_ONLY:
+        # and implements the functions defined below
+        for function_name in ["save", "read_asn", "from_asn"]:
+            function = getattr(C, function_name, None)
+            if function is None or not callable(function):
                 return False
 
+            # check that functionaccepts the required arguments/parameter
+            signature = inspect.signature(function)
+            target_signature = inspect.signature(getattr(cls, function_name))
+            for parameter_name in target_signature.parameters:
+                if parameter_name == "self":
+                    pass
+                # check that this required parameter/argument exists in the function signature
+                if parameter_name not in signature.parameters:
+                    return False
+                parameter = signature.parameters[parameter_name]
+                # make sure the required parameter is not positional only
+                if parameter.kind == inspect.Parameter.POSITIONAL_ONLY:
+                    return False
+
         return True
 
     @property
@@ -83,3 +79,31 @@ def save(self, path, save_model_func):
             List of output file paths of where the models were saved.
         """
         pass
+
+    @staticmethod
+    @abc.abstractmethod
+    def read_asn(filepath):
+        """
+        Load from an association file.
+
+        Parameters
+        ----------
+        filepath : str
+            The path to an association file.
+        """
+        pass
+
+    @abc.abstractmethod
+    def from_asn(self, asn_data, asn_file_path=None):
+        """
+        Load files from an association file.
+
+        Parameters
+        ----------
+        asn_data: dictionary
+            An association dictionary.
+
+        asn_file_path : str or None
+            Filepath of the association, if known.
+        """
+        pass