merge two ranges

[anoweb]

I have two ranges of numbers and I need to determine if they overlap
or adjacent and if so return a new range containing the values.  The
values are low and high for each pair, such that the first value of
the tuple is always less than or equal to the second value in the
tuple.

for example:
a = (0, 5)
b = (5, 10)

print getAdjacent(a, b)  # output: (0, 10)
print getAdjacent(b, a)  # output: (0, 10)
print getOverlap(a, b) # output: None
print getOverlap(b, a) # output: None

a = (0, 7)
b = (3, 10)
print getAdjacent(a, b) # output: None
print getAdjacent(b, a) # output: None
print getOverlap(a, b)  # output: (0, 10)
print getOverlap(b, a)  # output: (0, 10)

a = (0, 90)
b = (5, 10)
print getAdjacent(a, b) # output: None
print getAdjacent(b, a) # output: None
print getOverlap(a, b)  # output: (0, 90)
print getOverlap(b, a)  # output: (0, 90)

a = (0, 5)
b = (12, 20)
print getAdjacent(a, b) # output: None
print getAdjacent(b, a) # output: None
print getOverlap(a, b)  # output:None
print getOverlap(b, a)  # output: None

any easy way of doing this?