class Structure:
    _fields = ()

    def __init__(self, *args):
        if len(args) != len(self._fields):
            raise TypeError(f'Expected {len(self._fields)} arguments')
        for pos, field in enumerate(self._fields):
            setattr(self, field, args[pos])

    def __repr__(self):
        args = map(lambda field: f"{field}={getattr(self, field)!r}", self._fields)
        return f"{type(self).__name__}({', '.join(args)})"

    def __setattr__(self, name, value):
        if name in self._fields or name[0] == '_':
            super().__setattr__(name, value)
        else:
            raise AttributeError(f"No attribute {name}")