Difference of three input integers Implement a function diff that takes as input three integers x, y, and z. It should return whether subtracting one of these numbers from another gives the third.

Test cases:
diff(5, 3, 2) yields True because 5 - 3 = 2
diff(2, 3, 5) yields True because 5 - 3 = 2
diff(2, 5, 3) yields True because 5 - 3 = 2
diff(-2, 3, 5) yields True because 3 - 5 is -2
diff(-5, -3, -2) # -5 - -2 is -3
diff(2, 3, -5) yields False
diff(10, 6, 4) yields True because 10 - 6 = 4
diff(10, 6, 3) yields False


You don't have to name the function, you may implement default input methods the examples above are not a strict guideline.
Python 3, 21 bytes
lambda*l:sum(l)/2in l

If two numbers add to the other, the sum of all three will be double that other number, so half the sum will be an element of the list. Python 3 is needed to avoid floor-division, unless the numbers are given like 3.0 rather than 3.