Define a parent class called FiniteSet whose __init__ takes
as input a list of distinct elements and has one method, card()
which returns the cardinality of the set. Define a class called
FiniteMetricSpace which derives from FiniteSet and whose __init__
takes two inputs, a list of distinct elements of the underlying
set and a dictionary whose keys are all the pairs of points in
this set and values are the corresponding ditances. This class
should have an additional method dist(x,y) which takes two points
in the set and returns the distance between them. When complete
your code should tally with the following session:

>>> F = FiniteSet([2, 3])
>>> F.card()
2
>>> G = FiniteMetricSpace([2, 3], {(2, 3):1, (3,2):1, (2,2):0, (3,3):0})
>>> G.card()
2
>>> G.dist(2,3)
1


NOTE:

I explored some more and found that the problem we were having with
super() is some Python 2.7 nonsense about "old style" and "new style"
classes.  To announce to Python 2.7 that Point is a "new style"
class we have to define it as "class Point(object):" not just
"class Point:"  With this change, the call to super() works as
documented.  See allpoint.py for an updated version of the experimental
code we discussed in class with this change.  (In Python 3.x this "old
class" and "new class" stuff is not there, so the original code works
fine.)