Using python please

You have a list of students' names and their grades (in exams taken in PTSL course) in the form of word-colon-number (i.e. 'Student_name:Grade'). You need to complete the following Python function which will find the sum of all grades of each student and will return a dictionary where the key is the student name and its value is the total sum. For example, if the list is: l'Ahmad:15', 'Ali:20', 'Sara:16', 'Ahmad:12', 'Ali:30'] The function will return the following dictionary: {"Ahmad': 27, 'Ali': 50, 'Sara':16} def checkStudentsum(std_list)