This module is intended to ease access to nested data
structures—in any combination of key or attribue access to each
level of a hierarchy—where many paths in the tree may be missing.
Typically, such data is encountered in semi-structured formats
like JSON, YAML, or some XML, that is deserialized into Python
data structures.

PEP 505 attempts to address this need with the addition of a
number of new syntactic operators for attribute or item access
where a special type of failure mode "coalesces" None values.
Other libraries such as PyMaybe (https://pymaybe.readthedocs.io)
perform a similar operation, and are more mature and robust.

On the other hand, by utilizing `wrapt.ObjectProxy`, this simple
module manages to do some pretty neat stuff that even PyMaybe does
not.

In this library, I simply want to provide simple wrapper classes that
provide both what I think is more useful behavior and behavior that
is semantically equivalent to PEP 505.

Classes:

    GreedyAccess: 
    
        Wrap an object so that nested attribute and item access
        simply does not fail, but propagates a wrapped object 
        across such nested access.

    NullCoalesce:

        Wrap an object so that encountering a None (or other
        indicated sentinel) at any level stops accessing further 
        attributes and unboxes as a None (or other sentinel).

        Aliased as `NoneCoalesce`