diff --git a/src/jcloud_docsgen/cli.py b/src/jcloud_docsgen/cli.py
index 33c3300..0ff0a18 100644
--- a/src/jcloud_docsgen/cli.py
+++ b/src/jcloud_docsgen/cli.py
@@ -22,11 +22,10 @@ __all__ = [
 
 import argparse
 import pathlib
-from .utils import ExistingDirectory
 
-def existing_directory(path: str, *args, **kwargs) -> pathlib.Path:
+def existing_directory(path: str) -> pathlib.Path:
     try:
-        return ExistingDirectory(path, *args, **kwargs)
+        return pathlib.Path(path)
     except (FileNotFoundError, NotADirectoryError) as e:
         raise argparse.ArgumentTypeError(f'{e.filename}{": " + e.args[1] if len(e.args) > 1 else ""}')
 
diff --git a/src/jcloud_docsgen/core/python/_core.py b/src/jcloud_docsgen/core/python/_core.py
index 4b2405f..a4db189 100644
--- a/src/jcloud_docsgen/core/python/_core.py
+++ b/src/jcloud_docsgen/core/python/_core.py
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 from __future__ import annotations
-from ...utils import ExistingDirectory, assert_that_is_instance, ExistingFile, non_empty_str, get_relative_path_segments
+from ...utils import non_empty_str, get_relative_path_segments
 from ...exceptions import PythonArgumentStructureError, InvalidNamespaceError
 from .namespaces import PythonModuleNamespace, PythonPackageNamespace
 from .definitions import PythonDefinition, PythonFunctionDefinition, PythonAsyncFunctionDefinition, PythonClassDefinition
@@ -742,11 +742,11 @@ class PythonModuleDocumentationGenerator:
     A documentation generator for a Python module.
 
     :param module_path: The path of the module file.
-    :type module_path: ExistingFile
+    :type module_path: pathlib.Path
     :param src_directory: The directory of the source code. It is
                           optional and only used for making the module
                           identifiers in the documentation relative.
-    :type src_directory: Union[ExistingDirectory, None]
+    :type src_directory: Union[pathlib.Path, None]
     :param include_sections: The sections that will be included.
     :type include_sections: PythonDefinitionDocumentationIncludeSections
     :param kwargs: The options for ``PythonDefinitionDocumentationGenerator``.
@@ -754,15 +754,11 @@ class PythonModuleDocumentationGenerator:
 
     def __init__(
             self,
-            module_path: ExistingFile,
-            src_directory: Union[ExistingDirectory, None] = None,
+            module_path: pathlib.Path,
+            src_directory: Union[pathlib.Path, None] = None,
             include_sections: PythonDefinitionDocumentationIncludeSections = PythonDefinitionDocumentationIncludeSections(),
             **kwargs
         ) -> None:
-
-        assert_that_is_instance(module_path, ExistingFile)
-        assert_that_is_instance(src_directory, (ExistingDirectory, types.NoneType))
-
         if module_path.name.count('.') > 1:
             raise InvalidNamespaceError('namespace identifier cannot contain more than one dot', namespace_identifier = module_path.name)
 
@@ -877,8 +873,8 @@ def _generate_package_namespace_documentation(
                 documentation_directory / (sub_namespace.name + '.md')
             ).write_text(
                 PythonModuleDocumentationGenerator(
-                    ExistingFile(str(dir / (sub_namespace.name + '.py'))),
-                    ExistingDirectory(str(root_directory)),
+                    pathlib.Path(str(dir / (sub_namespace.name + '.py'))),
+                    pathlib.Path(str(root_directory)),
                     include_sections,
                     **kwargs
                 ).generate_documentation()
@@ -889,9 +885,9 @@ class PythonDocumentationGenerator:
     The class for the documentation generator.
 
     :param project_directory: The directory of the project.
-    :type project_directory: ExistingDirectory
+    :type project_directory: pathlib.Path
     :param docs_directory: The directory for the generated documentation.
-    :type docs_directory: ExistingDirectory
+    :type docs_directory: pathlib.Path
     :param include_sections: The sections to be included in the documentation.
     :type include_sections: PythonDefinitionDocumentationIncludeSections
     :param kwargs: The options for ``PythonDefinitionDocumentationGenerator``.
@@ -899,14 +895,11 @@ class PythonDocumentationGenerator:
 
     def __init__(
             self,
-            project_directory: ExistingDirectory,
-            docs_directory: ExistingDirectory,
+            project_directory: pathlib.Path,
+            docs_directory: pathlib.Path,
             include_sections: PythonDefinitionDocumentationIncludeSections = PythonDefinitionDocumentationIncludeSections(),
             **kwargs
         ) -> None:
-        assert_that_is_instance(project_directory, ExistingDirectory)
-        assert_that_is_instance(docs_directory, ExistingDirectory)
-
         self.project_directory = pathlib.Path(str(project_directory))
         self.docs_directory = pathlib.Path(str(docs_directory))
         self.include_sections = include_sections