Find the greatest number in a list of numbers

What about max()

highest = max(1, 2, 3)  # or max([1, 2, 3]) for lists

You can use the inbuilt function max() with multiple arguments:

print max(1, 2, 3)

or a list:

list = [1, 2, 3]
print max(list)

or in fact anything iterable.