Please help solve this in Python!!

You are given an input file with multiple pairs of input lines. The first line of each pair is a tree given as a predecessor array. The second line is the value at the corresponding node. Values at leaf nodes (nodes with no children) are integers. At non-leaf nodes, the two possible values are + or .

The tree represents an arithmetic expression where the value at a non-leaf node u is the sum of values at the children of u in the case of +, or the product of values at the children of u in the case of .

You need to calculate the value at each node and output the calculated value at the root. The tree is not constrained to be binary.

Input format:

Input consists of m pairs of lines of comma separated values, so 2m lines in total. The first line is each pair is a comma separated list of integers representing a tree in predecessor array format where 1 represents null.

The second line in each pair is a comma separated list of integers and the symbols + and . The ith item on the list is the value or operator at the ith node in the tree.

For example:

-1,0,0,0,1,1

+,*,2,3,0,7

2,0,-1,0

+,3,*,3

Output format:

For each pair of input lines, output a line containing the value calculated at the root of the tree.

For the example input above, output would be:

5

6