Bracket support signes -(+

solve the issue of two sines and one sandwiched bracket.

Look at the calculator's parsing logic for handling brackets and operators, likely in a file like parser.py or evaluator.py. Run existing tests to see how expressions with signs and brackets are currently processed. The goal is to correctly evaluate expressions like -(+ with two sines and a sandwiched bracket, but the issue does not specify the exact input or expected output.

索引モデルが issue の本文から書いたものです。