def METHOD_NAME(self, unique: bool = False, length: t.Optional[int] = None) -> str:
    """Generate random string value.
    This method can be especially useful when you need to generate
    only unique values in your provider. Just pass parameter unique=True.
    Basically, this method is just a simple wrapper around :py:class:`uuid.UUID`.
    :param unique: Generate only unique values.
    :param length: Length of string. Default range is [a, b].
    :return: Random string.
    """
    if unique:
        return str(uuid.uuid4().hex)
    if length is None:
        length = self.randint(16, 128)
    characters = string.ascii_letters + string.digits
    return "".join(self.choices(characters, k=length))