Traits 6.2 is the latest feature release in the Traits 6 series, with several
improvements and fixes over Traits 6.1.

Highlights of this release

The Traits examples are now distributed as part of the Traits egg, and
are contributed to the etsdemo application. (The latter can be
installed from PyPI with pip install etsdemo.)
Performance of the observe framework has been significantly improved.
It's no longer necessary to specify a trait comparison mode of
ComparisonMode.identity when using observe to observe items
in a List, Dict or Set.
Support for Python 3.5 has been dropped.
When importing from Traits, you should always import from one of the api
modules (for example, traits.api, traits.adaptation.api, etc.) This
recommendation has now been made explicit in the documentation. If you find
something you need that's not available from one of the api modules,
please let the Traits developers know.

Detailed PR-by-PR changes

More than 60 PRs went into this release. The following people contributed to
this release:

The Property trait type now supports the observe keyword. (#1175,
#1400)
Add |= support to TraitDict for Python 3.9 and later. (#1306)
Add casting keyword to numeric array types. (#547)
The Traits examples are now part of the Traits package, and so are
contributed to etsdemo. (#1275)
The Traits examples package now includes a beginner's tutorial. (#1061)

Parsing of the observe string was previously a performance bottleneck.
This has been fixed, by removing some redundant parsing calls and by caching
parsing results. (#1343, #1344, #1345)

The NoDefaultSpecified constant (used as a default value for
the TraitType default_value argument) is now public, made
available from traits.api. (#1384, #1380, #1378)
The deprecation of the TraitMap trait type has been reversed, because
there are existing uses of TraitMap that are hard to replace.
Nevertheless, it is still not recommended to use TraitMap in new code.
Use Map instead. (#1365)
An attempt to use PrefixList with an empty list, or PrefixMap or
Map with an empty dictionary, now raises ValueError. As a result,
the default default value (which used to be None) is always valid.
(#1351)
TraitListEvent arguments are now keyword only. (#1346)
It's no longer necessary to specify a trait comparison mode of
ComparisonMode.identity when using observe to observe items
in a List, Dict or Set. (#1165, #1328, #1240)

The Function and Method trait types are deprecated. Use
Callable or Instance instead. (#1399, #1397)
The edit parameter to configure_traits has been deprecated. (#1311)
The UnittestTools._catch_warnings function has been deprecated. (#1310)
The use of the CHECK_INTERFACES global variable for automated
interface checking has been deprecated. (#1231)

Non-TraitError exceptions raised during Tuple validation are now
propagated. Previously they were converted into TraitError. (#1393)
Dynamic Range and Enum traits are now properly validated
when inside a container (for example Tuple or List). Previously
no validation was performed. (#1388, #1392)
Remove the unused module-level constant traits.has_traits.EmptyList.
(#1366)
Don't hard-code class names in __repr__ implementations of
TraitListEvent, TraitSetEvent and TraitDictEvent. (#1335)
Don't notify on empty update\ s of Dict traits. (#1308)
Fix exception raised when assigning a NumPy array to a List
trait. (#1278)
Fix uses of deprecated logger.warn function. (#1283)
Fix a bad Instance trait declaration for a private trait in
the _TraitChangeCollector class. (#1411)

Add "Tutorial" section to the main documentation, based on the
new traits.examples tutorial content. (#1374)
Clarify that only the api modules should be used for imports. (#1387)
Update copyright header end years. (#1376)
Update contents of image_LICENSE.txt. (#1362)
Remove mentions of the removed functions adapts and implements from
the examples and tutorial. (#1367)
Move Traits introduction description to index.rst. (#1358)
Fix path to Enthought logo when building docset. (#1285)
Fix the trait_documenter extension to be less fragile. (#1247)
Add user manual documentation for the Instance trait type. (#1395)
Document that the List, Dict and Set trait types copy on
assignment. (#1402)
Various other minor improvements, typo fixes, and other documentation fixes.
(#1396, #1383, #1381, #1384, #1292, #1355, #1350, #1319, #1292, #1401)

Remove dead code. (#1281)
Update super usage to the usual Python 3 argument-less pattern. (#1280)
Remove per-import # noqa comments in api modules in favour of
per-file ignores in the flake8 configuration. (#1269)
Remove out-of-date and non-functional coverage badge from README. (#1263)
Rename _i_observable module to i_observable. (#1296)
Refactor and simplify method checks. (#1176)
Fix typo in optional_dependencies comment. (#1235)
Use ComparisonMode constants instead of magic numbers. (#1229)

Prevent test_enum failures if traitsui or GUI toolkit are not installed.
(#1349)
Tests that require pkg_resources are skipped if setuptools is not
installed. (#1301)
Fix an order-dependency bug in the test_subclasses_weakref regression
test. (#1290)
Fix a typo in a test method name. (#1309)
Various additional or improved tests for existing code.
(#1359, #1336, #1330, #1248, #1225, #1208, #1209)

Traits now uses GitHub Actions for continuous integration. The Travis CI
and Appveyor configurations have been removed. (#1296, #1360)
CI runs are no longer based on EDM. (#878)
New CI run for the core test suite, without any optional dependencies.
(#1314)
Test Python 3.9 in the continuous integration (and drop tests for Python
3.5 and older). (#1326, #1313, , #1303)
Make traits.examples into a package. (#1348)
Make examples directories flake8-clean. (#1353)
Fix examples packaging nit. (#1363)
Support -h for getting help in etstool.py. (#1347)
Add shell command to etstool.py. (#1293)
Use the flake8_ets package in place of the local copyright_header
package.
The copyright_header package has been removed. (#1341)
Add script check_observe_timing.py to benchmark performance of
observe to compare with on_trait_change. (#1331)
Correct the minimum Sphinx version in README. (#1216, #1320)
Restrict Sphinx version to avoid buggy versions. (#1276)
Make mypy an optional dependency. (#1289)
Speed up CI builds for Travis and Appveyor by caching the pip directory
(now redundant). (#1241)
Add automated wheel and sdist building for Traits releases. (#1404, #1291)
Add cron-job workflow to regularly test install of the latest releases
from PyPI. (#1406)