In python, write logic for the following code:

def total(val): #logic def sub(val): #logic def times(val): #logic def div(val): #logic 

REQUIREMENTS

def total(val) - returns sum of all # in the list 'val'.

def sub(val) - returns the difference of all # in the list 'val'.

def times(val) - returns the product of all # in the list 'val'.

def div(val) - returns the result of dividing all # in the list 'val'. If first # is 0, then the result is 0. If any other # are 0, use sys.exit to stop it & display 'invalid list.'