Write a program that finds the summation of every number from 1 to num. The number will always be a positive integer greater than 0.

summation(2) # returns 3
summation(8) # returns 36
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def summation(num):    
    return sum([i for i in range(1, num+1)])
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def summation(num):
    return sum(xrange(num + 1))
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def summation(num):
    return sum(range(1,num+1))
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• List comprehension here is completely unnecessary, because range itself returns an iterable (it itself is not an iterator, there is a difference) that you can still use sum on.
• xrange is a Python2 relic and has been removed.