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memoized() used id() to get "unique" representations for arguments passed to a function, in order to ensure that results for the same function called with different arguments are treated differently. However, Python object identities are only guaranteed to be unique at a particular point in time. It is possible than a particular ID gets reused for a different object if the previous object associated with that ID no longer exists. In particular, in CPython, the IDs are just addresses of the corresponding PyObject's in memory. If a PyObject gets garbage collected, another object may get allocated in its place, and the new object will "inherit" the ID by virtue of being in the same memory location. If the new object is then used to call a memoized function that was previously called with the old object, the old cached result will be incorrectly returned. To get around this issue, the cache is now indexed not only by the ID of an object but also but the first few bytes of its value. NOTE: there is still a potential issue it two relatively large objects gets allocated in the same place and happen to share the first few (currently 32) bytes, and are then both used as parameters to the same memoized function. The only way around that is to hash the entire value of the object. However, given the performance penalty that would incur for larger object, and the unlikeliness of this situation actually arising, it is currently deemed not worth it.
devlib
======
``devlib`` exposes an interface for interacting with and collecting
measurements from a variety of devices (such as mobile phones, tablets and
development boards) running a Linux-based operating system.
Installation
------------
::
sudo -H pip install devlib
Usage
-----
Please refer to the "Overview" section of the documentation.
License
-------
This package is distributed under `Apache v2.0 License <http://www.apache.org/licenses/LICENSE-2.0>`_.
Feedback, Contrubutions and Support
-----------------------------------
- Please use the GitHub Issue Tracker associated with this repository for
feedback.
- ARM licensees may contact ARM directly via their partner managers.
- We welcome code contributions via GitHub Pull requests. Please try to
stick to the style in the rest of the code for your contributions.