diff --git a/src/protean/core/aggregate.py b/src/protean/core/aggregate.py
index c88d05f8..387345bb 100644
--- a/src/protean/core/aggregate.py
+++ b/src/protean/core/aggregate.py
@@ -64,6 +64,8 @@ def __new__(cls, *args, **kwargs):
     def __init_subclass__(subclass) -> None:
         super().__init_subclass__()
 
+        # Event-Sourcing Functionality
+        #
         # Associate a `_projections` map with subclasses.
         #   It needs to be initialized here because if it
         #   were initialized in __init__, the same collection object
@@ -71,6 +73,8 @@ def __init_subclass__(subclass) -> None:
         #   defeating its purpose.
         setattr(subclass, "_projections", defaultdict(set))
 
+        # Event-Sourcing Functionality
+        #
         # Store associated events
         setattr(subclass, "_events_cls_map", {})
 
@@ -99,7 +103,9 @@ def _default_options(cls):
         ]
 
     def _apply(self, event: BaseEvent) -> None:
-        """Apply the event onto the aggregate by calling the appropriate projection.
+        """Event-Sourcing Functionality
+
+        Apply the event onto the aggregate by calling the appropriate projection.
 
         Args:
             event (BaseEvent): Event object to apply
@@ -120,7 +126,10 @@ def _apply(self, event: BaseEvent) -> None:
 
     @classmethod
     def from_events(cls, events: List[BaseEvent]) -> "BaseAggregate":
-        """Reconstruct an aggregate from a list of events."""
+        """Event-Sourcing Functionality
+
+        Reconstruct an aggregate from a list of events.
+        """
         # Initialize the aggregate with the first event's payload and apply it
         aggregate = cls(**events[0].payload)
         aggregate._apply(events[0])
@@ -210,6 +219,7 @@ def aggregate_factory(element_cls, domain, **opts):
         f"{domain.normalized_name}::{element_cls.meta_.stream_category}"
     )
 
+    # Event-Sourcing Functionality
     # Iterate through methods marked as `@apply` and construct a projections map
     methods = inspect.getmembers(element_cls, predicate=inspect.isroutine)
     for method_name, method in methods:
@@ -240,7 +250,10 @@ def __exit__(self, *args):
 
 
 def apply(fn):
-    """Decorator to mark methods in EventHandler classes."""
+    """Event-Sourcing Functionality
+
+    Decorator to mark methods in EventHandler classes.
+    """
 
     if len(typing.get_type_hints(fn)) > 2:
         raise IncorrectUsageError(
diff --git a/src/protean/domain/__init__.py b/src/protean/domain/__init__.py
index d45ea172..a0c2545f 100644
--- a/src/protean/domain/__init__.py
+++ b/src/protean/domain/__init__.py
@@ -968,11 +968,12 @@ def _setup_event_handlers(self):
 
     def _generate_fact_event_classes(self):
         """Generate FactEvent classes for all aggregates with `fact_events` enabled"""
-        for element_type in [DomainObjects.AGGREGATE]:
-            for _, element in self.registry._elements[element_type.value].items():
-                if element.cls.meta_.fact_events:
-                    event_cls = element_to_fact_event(element.cls)
-                    self.register(event_cls, part_of=element.cls)
+        for _, element in self.registry._elements[
+            DomainObjects.AGGREGATE.value
+        ].items():
+            if element.cls.meta_.fact_events:
+                event_cls = element_to_fact_event(element.cls)
+                self.register(event_cls, part_of=element.cls)
 
     ######################
     # Element Decorators #
@@ -1209,8 +1210,10 @@ def repository_for(self, element_cls) -> BaseRepository:
             element_cls.element_type == DomainObjects.AGGREGATE
             and element_cls.meta_.is_event_sourced
         ):
+            # Return an Event Sourced repository
             return self.event_store.repository_for(element_cls)
         else:
+            # This is a regular aggregate or a view
             return self.providers.repository_for(element_cls)
 
     #######################
diff --git a/src/protean/fields/association.py b/src/protean/fields/association.py
index 4278c165..83c3a78c 100644
--- a/src/protean/fields/association.py
+++ b/src/protean/fields/association.py
@@ -377,6 +377,7 @@ def __set__(self, instance, value):
         The `temp_cache` we set up here is eventually used by the `Repository` to determine
         the changes to be persisted.
         """
+        # Accept dictionary values and convert them to Entity objects
         if isinstance(value, dict):
             value = self.to_cls(**value)
 
@@ -485,6 +486,7 @@ def __set__(self, instance, value):
         """
         value = value if isinstance(value, list) else [value]
 
+        # Accept dictionary values and convert them to Entity objects
         values = []
         for item in value:
             if isinstance(item, dict):
diff --git a/src/protean/utils/__init__.py b/src/protean/utils/__init__.py
index 9182cbda..7fed2290 100644
--- a/src/protean/utils/__init__.py
+++ b/src/protean/utils/__init__.py
@@ -4,7 +4,6 @@
 to the maximum extent possible.
 """
 
-import functools
 import importlib
 import logging
 from datetime import UTC, datetime
@@ -73,14 +72,6 @@ def get_version():
     return importlib.metadata.version("protean")
 
 
-def import_from_full_path(domain, path):
-    spec = importlib.util.spec_from_file_location(domain, path)
-    mod = importlib.util.module_from_spec(spec)
-    spec.loader.exec_module(mod)
-
-    return getattr(mod, domain)
-
-
 def fully_qualified_name(cls):
     """Return Fully Qualified name along with module"""
     return ".".join([cls.__module__, cls.__qualname__])
@@ -89,19 +80,6 @@ def fully_qualified_name(cls):
 fqn = fully_qualified_name
 
 
-def singleton(cls):
-    """Make a class a Singleton class (only one instance)"""
-
-    @functools.wraps(cls)
-    def wrapper_singleton(*args, **kwargs):
-        if not wrapper_singleton.instance:
-            wrapper_singleton.instance = cls(*args, **kwargs)
-        return wrapper_singleton.instance
-
-    wrapper_singleton.instance = None
-    return wrapper_singleton
-
-
 def convert_str_values_to_list(value):
     if not value:
         return []
@@ -184,7 +162,7 @@ def generate_identity(
         elif id_type == IdentityType.UUID.value:
             id_value = uuid4()
         else:
-            raise ConfigurationError(f"Unknown Identity Type {id_type}")
+            raise ConfigurationError(f"Unknown Identity Type '{id_type}'")
 
     # Function Strategy
     elif id_strategy == IdentityStrategy.FUNCTION.value:
@@ -214,7 +192,5 @@ def generate_identity(
     "fully_qualified_name",
     "generate_identity",
     "get_version",
-    "import_from_full_path",
-    "singleton",
     "utcnow_func",
 ]
diff --git a/tests/test_containers.py b/tests/test_containers.py
index 4a5bd44b..40eebb53 100644
--- a/tests/test_containers.py
+++ b/tests/test_containers.py
@@ -1,7 +1,7 @@
 import pytest
 
 from protean.container import BaseContainer, OptionsMixin
-from protean.exceptions import InvalidDataError
+from protean.exceptions import InvalidDataError, NotSupportedError
 from protean.fields import Integer, String
 from protean.reflection import declared_fields
 
@@ -18,6 +18,11 @@ class CustomContainer(CustomContainerMeta, OptionsMixin):
     bar = String()
 
 
+def test_that_base_container_class_cannot_be_instantiated():
+    with pytest.raises(NotSupportedError):
+        BaseContainer()
+
+
 class TestContainerInitialization:
     def test_that_base_container_class_cannot_be_instantiated(self):
         with pytest.raises(TypeError):
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 00000000..0eece996
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,56 @@
+import pytest
+
+from protean.exceptions import ConfigurationError
+from protean.utils import convert_str_values_to_list, generate_identity
+
+
+def test_convert_str_values_to_list():
+    # Test when value is None
+    assert convert_str_values_to_list(None) == []
+
+    # Test when value is an empty string
+    assert convert_str_values_to_list("") == []
+
+    # Test when value is a non-empty string
+    assert convert_str_values_to_list("test") == ["test"]
+
+    # Test when value is a list of strings
+    assert convert_str_values_to_list(["a", "b"]) == ["a", "b"]
+
+    # Test when value is a list of integers
+    assert convert_str_values_to_list([1, 2, 3]) == [1, 2, 3]
+
+    # Test when value is a tuple
+    assert convert_str_values_to_list((1, 2, 3)) == [1, 2, 3]
+
+    # Test when value is a set
+    assert convert_str_values_to_list({1, 2, 3}) == [1, 2, 3]
+
+    # Test when value is a dictionary
+    assert convert_str_values_to_list({"a": 1, "b": 2}) == ["a", "b"]
+
+    # Test when value is an integer (not iterable)
+    with pytest.raises(TypeError):
+        convert_str_values_to_list(10)
+
+    # Test when value is a float (not iterable)
+    with pytest.raises(TypeError):
+        convert_str_values_to_list(10.5)
+
+    # Test when value is a boolean
+    with pytest.raises(TypeError):
+        convert_str_values_to_list(True)
+
+    # Test when value is an object
+    class TestObject:
+        pass
+
+    with pytest.raises(TypeError):
+        convert_str_values_to_list(TestObject())
+
+
+def test_unknown_identity_type_raises_exception():
+    with pytest.raises(ConfigurationError) as exc:
+        generate_identity(identity_type="foo")
+
+    assert str(exc.value) == "Unknown Identity Type 'foo'"