cmath is a mathematical module that is present in python to convert complex numbers to polar numbers Doubt: why we use * in cmath as *cmath need to know this (it is raised in polar coordinates problem hacker rank) we use * because it clears the brackets and take the input from spaces of lists rpartition() function in Python split the given string into three parts . rpartition() start looking for separator from right side, till the separator is found and return a tuple which contains part of the string before the separator, the argument of the string, and the part after the separator In Python 3 we use // for integer division Since set elements must be hashable, and lists are considered mutable, you cannot add a list to a set . Try Except in Python The try block is used to check some code for errors i.e the code inside the try block will execute when there is no error in...