Please help with these mini problems and explain..new Python 3 user coming from C background..

1. What I wrote on the right side will not execute..

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3.

sum csv string Sum a CSV-format string of numbers def sum csv stringCcsv string Write a function sum csv string(csv string) that behaves as your code here follows: #def listsum list its argument csv string is a string of comma-separated values, 5 thisSum 0 with each value in the string being a sequence of decimal digits. It returns an integer that is the sum of the numerical values in the for i in csv string string. this Sum i Author: Saumya Debray return this Sum License Not redistributable 10 11 The test case 12 print sum-csv stringCC2.0,3.0,4.00 Should output 9