The base example is to use a try/except block. You can raise exceptions in code that can be caught by the except block.

try:
    linux_interaction()
except:
    print('Linux function was not executed')
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class LinkedList:
    def __init__(self, head=None):
        self.head = head

    def getFirst(self):
        if self.head == None:
            raise Exception("No items in list")
        else:
            return self.head

try:
    ll = LinkedList()
    ll.getFirst()
except Exception, error:
    print(error)
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