from pathlib import Path
from typing import NewType

UnsanitizedText = NewType('UnsanitizedText', str)
CleanHtml = NewType('CleanHtml', str)
HtmlTemplate = NewType('HtmlTemplate', str)

def get_user_input() -> UnsanitizedText:
    # code omitted

def escape_to_html(raw: UnsanitizedText) -> CleanHtml:
    # perform checks on 'raw', do escaping logic, etc
    return CleanHtml(cleaned_string)

def load_template(path: Path) -> HtmlTemplate:
    return HtmlTemplate(path.read_text())

def render_template(template: HtmlTemplate, *kwargs: CleanHtml) -> CleanHtml:
    # code omitted

t = load_template(Path("foo/bar.html"))
dirty = get_user_input()
clean = escape_to_html(dirty)

print(render_template(t, arg=dirty))  # Does not typecheck
print(render_template(t, arg=clean))  # Typechecks