diff --git a/cppython/project.py b/cppython/project.py
index 1f2af26..63f7bf6 100644
--- a/cppython/project.py
+++ b/cppython/project.py
@@ -36,7 +36,9 @@ class ProjectBuilder:
     def __init__(self, configuration: ProjectConfiguration) -> None:
         self.configuration = configuration
 
-    def gather_plugins(self, plugin_type: Type[Plugin]) -> list[Type[Plugin]]:
+    DerivedPlugin = TypeVar("DerivedPlugin", bound=Plugin)
+
+    def gather_plugins(self, plugin_type: Type[DerivedPlugin]) -> list[Type[DerivedPlugin]]:
         """
         TODO
         """
@@ -50,7 +52,7 @@ def gather_plugins(self, plugin_type: Type[Plugin]) -> list[Type[Plugin]]:
 
         return plugins
 
-    def generate_model(self, plugins: list[Type[Plugin]]) -> Type[PyProject]:
+    def generate_model(self, plugins: list[Type[Generator]]) -> Type[PyProject]:
         """
         TODO
         """
@@ -58,21 +60,21 @@ def generate_model(self, plugins: list[Type[Plugin]]) -> Type[PyProject]:
         for plugin_type in plugins:
             plugin_fields[plugin_type.name()] = plugin_type.data_type()
 
-        ExtendedCPPythonData = create_model(
+        extended_cppython_type = create_model(
             "ExtendedCPPythonData",
             **plugin_fields,
             __base__=CPPythonData,
         )
 
-        ExtendedToolData = create_model(
+        extended_tool_type = create_model(
             "ToolData",
-            cppython=ExtendedCPPythonData,
+            cppython=extended_cppython_type,
             __base__=ToolData,
         )
 
         return create_model(
             "PyProject",
-            tool=ExtendedToolData,
+            tool=extended_tool_type,
             __base__=PyProject,
         )
 
@@ -110,8 +112,8 @@ def __init__(
                 interface.print("No generator plugin was found.")
             return
 
-        ExtendedPyProject = builder.generate_model(plugins)
-        pyproject = ExtendedPyProject(**pyproject_data)
+        extended_pyproject_type = builder.generate_model(plugins)
+        pyproject = extended_pyproject_type(**pyproject_data)
 
         if pyproject.tool is None:
             if self.configuration.verbose:
diff --git a/pdm.lock b/pdm.lock
index 0c31f8e..839d8c8 100644
--- a/pdm.lock
+++ b/pdm.lock
@@ -62,7 +62,7 @@ extras = ["toml"]
 requires_python = ">=3.7"
 summary = "Code coverage measurement for Python"
 dependencies = [
-    "coverage",
+    "coverage>=5.2.1",
     "tomli",
 ]
 
@@ -167,9 +167,9 @@ dependencies = [
 
 [[package]]
 name = "pyparsing"
-version = "3.0.7"
-requires_python = ">=3.6"
-summary = "Python parsing module"
+version = "3.0.8"
+requires_python = ">=3.6.8"
+summary = "pyparsing module - Classes and methods to define and execute parsing grammars"
 
 [[package]]
 name = "pytest"
@@ -462,9 +462,9 @@ content_hash = "sha256:f53b6399862b1bc49a0ad0dc5017dfeb3c9348259b7b5fbabf9c70536
     {file = "pylint-2.13.5-py3-none-any.whl", hash = "sha256:c149694cfdeaee1aa2465e6eaab84c87a881a7d55e6e93e09466be7164764d1e"},
     {file = "pylint-2.13.5.tar.gz", hash = "sha256:dab221658368c7a05242e673c275c488670144123f4bd262b2777249c1c0de9b"},
 ]
-"pyparsing 3.0.7" = [
-    {file = "pyparsing-3.0.7-py3-none-any.whl", hash = "sha256:a6c06a88f252e6c322f65faf8f418b16213b51bdfaece0524c1c1bc30c63c484"},
-    {file = "pyparsing-3.0.7.tar.gz", hash = "sha256:18ee9022775d270c55187733956460083db60b37d0d0fb357445f3094eed3eea"},
+"pyparsing 3.0.8" = [
+    {file = "pyparsing-3.0.8-py3-none-any.whl", hash = "sha256:ef7b523f6356f763771559412c0d7134753f037822dad1b16945b7b846f7ad06"},
+    {file = "pyparsing-3.0.8.tar.gz", hash = "sha256:7bf433498c016c4314268d95df76c81b842a4cb2b276fa3312cfb1e1d85f6954"},
 ]
 "pytest 7.1.1" = [
     {file = "pytest-7.1.1-py3-none-any.whl", hash = "sha256:92f723789a8fdd7180b6b06483874feca4c48a5c76968e03bb3e7f806a1869ea"},
diff --git a/tests/unit/test_project.py b/tests/unit/test_project.py
index 81d8e0f..58ac989 100644
--- a/tests/unit/test_project.py
+++ b/tests/unit/test_project.py
@@ -47,18 +47,18 @@ def test_generator_data_construction(self, mocker: MockerFixture):
 
         configuration = ProjectConfiguration()
         builder = ProjectBuilder(configuration)
-        Model = builder.generate_model([])
+        model_type = builder.generate_model([])
 
-        assert Model.__base__ == PyProject
+        assert model_type.__base__ == PyProject
 
         generator = mocker.Mock(spec=Generator)
         generator_data = mocker.Mock(spec=GeneratorData)
 
         generator.name.return_value = "mock"
         generator.data_type.return_value = type(generator_data)
-        Model = builder.generate_model([generator])
+        model_type = builder.generate_model([generator])
 
-        assert Model.__base__ == PyProject
+        assert model_type.__base__ == PyProject
 
     def test_generator_creation(self, mocker: MockerFixture):
         """