`dynamic_reducer` takes a list integers and an operator and does maths on list to sum integers.

dynamic_reducer.py

def dynamic_reducer(numbers, operator):
    result = numbers[0]
    for i in range(1, len(numbers)):
        if operator == "+":
            result += numbers[i]
        elif operator == "-":
            result -= numbers[i]
        elif operator == "*":
            result *= numbers[i]
        elif operator == "/":
            result /= numbers[i]
        else:
            raise ValueError("Invalid operator")
    return result


result = dynamic_reducer([1, 2, 3, 4, 5], "+")
print(result)