def METHOD_NAME(self, o: mypy.nodes.UnaryExpr) -> object:
    operand = o.expr.accept(self)
    if operand is UNKNOWN:
        return UNKNOWN
    if o.op == "-":
        if isinstance(operand, (int, float, complex)):
            return -operand
    elif o.op == "+":
        if isinstance(operand, (int, float, complex)):
            return +operand
    elif o.op == "~":
        if isinstance(operand, int):
            return ~operand
    elif o.op == "not":
        if isinstance(operand, (bool, int, float, str, bytes)):
            return not operand
    return UNKNOWN