You'll need to build a better version of your calculator using OOP and inheritance:
A calculator can be built with different operations. An Operation is an abstract class for which you'll define


calc1 = Calculator(operations={
    'add': AddOperation,
    'subtract': SubtractOperation})

calc2 = Calculator(operations={
    'add': AddOperation})

The calculator has 1 generic method calculate that will receive the arguments
and the operation to perform. For example:

calc1.calculate(2, 1, 5, 'add')  # Should return 2 + 1 + 5 = 8
calc2.calculate(1, 5, 'add')  # Should return 1 + 5 = 6

IMPORTANT: The number of arguments should be variable

The Calculator will check if it has that computation present and
invoke the operation. Operations are initialized with the arguments to compute:

op = AddOperation(2, 1, 5)

Once you have an operation object created you should be able to invoke the operate

op.operate()  # Should return 8

Important notes:
The only method that you must implement for every operation (descendant from Operation) is the operate method.
If the operation is not supported by the calculator (for example invoking multiply on calc1) the calculator should raise a custom exception (built by you) named OperationInvalidException.

Test Cases


class Operation(object): def __init__(self, *args): # Do something here pass def operate(self): raise NotImplementedError() class AddOperation(Operation): # The only method present in this class def operate(self): pass class SubtractOperation(Operation): def operate(self): pass class Calculator(object): pass