The semantics of __coerce__ have been changed to be more
reasonable. As an example, the new standard module Complex
implements fairly complete complex numbers using this. Additional
examples of classes with and without __coerce__ methods can be
found in the Demo/classes subdirectory, modules Rat and
Dates.
If a class defines no __coerce__ method, this is equivalent to
the following definition:
def __coerce__(self, other): return self, other
If __coerce__ coerces itself to an object of a different type,
the operation is carried out using that type -- in release 1.1, this
would cause an error.
Comparisons involving class instances now invoke __coerce__
exactly as if cmp(x, y) were a binary operator like +
(except if x and y are the same object).