def ensure_str(s):
    """ Ensure that s is a str and not a bytes (.decode() if necessary)

    >>> ensure_str(b"I'm 2. When I grow up I want to be a str!")
    "I'm 2. When I grow up I want to be a str!"
    >>> ensure_str(42)
    '42'
    """
    try:
        return s.decode()
    except AttributeError:
        if isinstance(s, str):
            return s
    return repr(s)
