Yes, we can update the program to handle text input. We can use the eval() function in Python to evaluate the expression string and return the result. Here's the updated code:

class Calculator:
    def __init__(self):
        pass

    def calculate(self, expression):
        try:
            result = eval(expression)
            return result
        except:
            return "Invalid expression"

Now, you can create an instance of the Calculator class and use the calculate() method to evaluate an expression:

calc = Calculator()
result = calc.calculate("2 + 10 / 5")  # result will be 4.0
result = calc.calculate("3 * 9 - 7")  # result will be 20

Note that eval() function can evaluate any Python expression. Therefore, it is important to make sure that the input is sanitized and comes from a trusted source. In this example, we have not added any input validation or sanitation, so it is vulnerable to code injection attacks.
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