many fixes to the inner project's __init__.py

{{cookiecutter.project_slug}}/src/{{cookiecutter.project_slug}}/__init__.py

@@ -1,8 +1,13 @@
-"""Top-level package for {{ cookiecutter.project_name }}."""
+"""Top-level package for {{cookiecutter.project_name}}."""
 
-__author__ = """{{ cookiecutter.full_name }}"""
-__email__ = '{{ cookiecutter.email }}'
-__version__ = '{{ cookiecutter.version }}'
+__all__ = [
+    "NODE_CLASS_MAPPINGS",
+    "NODE_DISPLAY_NAME_MAPPINGS",
+]
 
-import NODE_CLASS_MAPPINGS
-import NODE_DISPLAY_NAME_MAPPINGS
+__author__ = """{{cookiecutter.full_name}}"""
+__email__ = "{{cookiecutter.email}}"
+__version__ = "{{cookiecutter.version}}"
+
+from .nodes import NODE_CLASS_MAPPINGS
+from .nodes import NODE_DISPLAY_NAME_MAPPINGS