Your task is to create a function that does four basic mathematical operations.
The function should take three arguments - operation(string/char), value1(number), value2(number). The function should return result of numbers after applying the chosen operation.
('+', 4, 7) --> 11
('-', 15, 18) --> -3
('*', 5, 5) --> 25
('/', 49, 7) --> 7
def basic_op(operator, value1, value2)
value1.send(operator, value2)
end