A single-file package implementing a mutable, bidirectional, 1-to-1 mapping with O(1) item access.
Since every key in the bijection is also a value and vice-versa, the generic
type parameters A and B are used in place of the traditional K and V.
An instance of AbstractBijection[A, B] implements
typing.MutableMapping[A, B], and exposes an attribute called inv which is an
instance of AbstractBijection[B, A] and provides an inverted view of its
parent object. Both the bijection and its inverse support O(1) lookup and
deletion.
Usually, Bijection is the only class that you will need to explicitly
instantiate. AbstractBijection is usually a more correct choice for use in
type annotations.
See the doctests for examples.