foo.py

class BetterAddition:
    def __init__(self, arg):
        assert arg
        match arg:
            case str(): self.strVal = arg
            case int(): self.intVal = arg
            case _: print('int or str only')

    def __add__(self, other):
        assert other
        match other:
            case str(): return f"{(self.strVal if hasattr(self, 'strVal') else str(self.intVal))} {other}"
            case int():
                if hasattr(self, 'intVal'): return other + self.intVal
                else: return f'{self.strVal} {str(other)}'
            case _: print('give me a string or int value!')

    def __repr__(self):
        return (self.strVal if hasattr(self, 'strVal') else str(self.intVal))
w = BetterAddition
w(1) # 1
w('a') # 'a'
w(1) + 2 # 3
w(1) + 'b' # '1 b'
w('a') + 2 # 'a 2'
w('a') + 'b' # 'a b'