diff --git a/sbol3/identified.py b/sbol3/identified.py
index 36cd8c4..0d44b66 100644
--- a/sbol3/identified.py
+++ b/sbol3/identified.py
@@ -1,3 +1,4 @@
+import abc
 import math
 import posixpath
 from typing import Union, List, Callable, Any
@@ -22,6 +23,32 @@ def __init__(self, identity: str, type_uri: str,
                  *, name: str = None, description: str = None,
                  derived_from: List[str] = None, generated_by: List[str] = None,
                  measures: List[SBOLObject] = None) -> None:
+        """
+        :param identity: this object's Uniform Resource Identifier (URI).
+            this URI MUST be globally unique among all other Identified
+            object URIs. See SBOL 3.0.1 specification section 5.1.
+            This can also be a `displayId`, which will be concatenated
+            to a default namespace automatically.
+        :param type_uri: the concrete type of this object, specified as
+            a URI. These are typically in the SBOL3 namespace, like
+            `http://sbols.org/v3#Sequence` or
+            `http://sbols.org/v3#Component`. This can also be the type
+            URI of an extension class.
+        :param name: A human-readable name for this object, for display
+            purposes.
+        :param description: Per the SBOL 3.0.1 specification, "a more
+            thorough text description" of this object.
+        :param derived_from: The URIs of one or more SBOL or non-SBOL
+            objects from which this object was derived. This property
+            is defined by the PROV-O ontology.
+        :param generated_by: The URIs of one or more prov:Activity
+            objects that describe how this object was generated. This
+            property is defined by the PROV-O ontology.
+        :param measures: The URIs of one or more om:Measure objects,
+            each of which refers to a om:Measure object that describes
+            measured parameters for this object. om:Measure objects are
+            defined by the OM ontology
+        """
         super().__init__(identity)
         self._document = None
         self._display_id = TextProperty(self, SBOL_DISPLAY_ID, 0, 1)
@@ -208,7 +235,16 @@ def serialize(self, graph: rdflib.Graph):
                 graph.add((identity, rdf_prop, rdflib.URIRef(item.identity)))
                 item.serialize(graph)
 
+    @abc.abstractmethod
     def accept(self, visitor: Any) -> Any:
+        """
+        An abstract method for concrete classes to override. This
+        method is part of the visitor pattern implementation.
+
+        :param visitor: Ignored
+        :return: Unspecified
+        :raises: NotImplementedError if not overridden
+        """
         message = f'accept is not implemented for {type(self).__qualname__}'
         raise NotImplementedError(message)