Need Python Code for the following function with comments and screenshot of the code:

Assume we have a mathematical expression in postfix notation available as a string of operands and operators. The procedure for evaluating such a postfix expression is as follows: 1. Scan the expression left to right. 2. Skip values or variables (operands). 3. When an operator is found, apply the operation to the preceding two operands. 4. Replace the two operands and operator with the calculated value (three symbols are replaced with one operand). 5. Continue scanning until only a value remains -- the result of the expression Write a program that takes input a well-formed mathematical expression as a string in postfix notation and evaluates it using a stack. We assume the input to be already in post-fix form. Also, we are assuming only four binary operators {t, -, /, *} are allowed. >>> postfixEval("21 - 342 / + *") 5.0 >>> postfixEval("2 3 4 + * 6-") 8.0 >>> postfixEval("10.2 8 6 - * 3 / 112.5 +") 119.3