could u aid with this. Make sure to use strings and seperate the function and main file.

15. Implement the following function in the PyDev module functions. py and test it from a PyDev module named t15. py: Note the spaces between the numbers and the operator. def calculate(expr) : Treats expr as a math expression and evaluates it. expr must have the following format: operand1 operator operand2 operators are: +, -, *, /, % operands are one-digit integer numbers Return None if second operand is zero for division. Use: result = calculate(expr) Parameters: expr - an arithmetic expression to be calculated (str) Returns : result - The result of arithmetic expression (float) Sample testing: Enter an expression: 5 + 4 5+4 =9 Enter an expression: 8 % 4 8 % 4 = 0 Test functions . py: Choose File No file chosen Submit Results