python 3 module __getattr__ is neat

tags.py

from dataclasses import dataclass, field
from typing import Union


@dataclass
class _Tag:
    name: str
    attributes: dict[str, str] = field(default_factory=dict)
    children: tuple[Union["Tag", str]] = ()

    def __call__(self, *children, **attributes):
        return self.__class__(self.name, {**self.attributes, **attributes}, self.children + children)
    
    def render(self):
        tag = "<" + self.name
        if self.attributes:
            tag += " " + ''.join(f'{key}="{val}"' for key, val in self.attributes.items()) 
        if self.children:
            inner = "".join([v if isinstance(v, str) else v.render() for v in self.children])
            return f"{tag}>{inner}</{self.name}>"
        return f"{tag}/>"


def __getattr__(name):
    return _Tag(name)