Log Message:
py-music21: update to 6.1.0

Change log:

Music21 v6 is OUT as v6.1.0! This represents over 500 commits over the past 14 \ 
months since v5.7 was released.

Many thanks to Jacob Tyler Walls (JTW below) who made so many contributions to \ 
the v6 branch, both big and small. Mad props and round of applause!

v6 fully supports Python 3.8 and removes support for Python 3.5. v6 will be the \ 
last major release to support Python 3.6 and we will work on Python 3.9 support \ 
immediately.

As with all new v.X releases of music21 there are improvements and some \ 
backwards incompatible changes (not too many)

In no particular order, here are the things to look for in the new music21 v6:

    Type hints throughout music21 -- when you program with a sophisticated IDE \ 
you will be able to see what is returned and required as attributes in much of \ 
music21.

    music21 is no longer packaged with external modules; these will be installed \ 
when installing music21 via pip (otherwise run pip install -r requirements.txt). \ 
Speed and security improvements come with this.

    converter.parse('file.mid', quantizePost=False) will let you load in a MIDI \ 
file without any quantizing. (Thanks JTW)

    Lots more values cached = faster music21; RomanNumerals in particular are \ 
over an order of magnitude faster, and Chords are faster too. If you ever have a \ 
problem, all Music21Objects have a .clearCache() function. Just add @cacheMethod \ 
as a decorator to a method and it will use the caching routine.

    Intervals have been rewritten to use properties entirely. So whatever \ 
happens to an Interval, its semiSimpleNiceName (to take one of dozens of \ 
examples) will always be up to date. Intervals use Specifiers that are enums \ 
like interval. Specifier.PERFECT instead of inscrutable numbers. (those \ 
inscrutable numbers still work though) Specifiers are more than just standard \ 
enums -- they can invert themselves, do semitonesAboveMajor() etc. Interval \ 
geeks rejoice.

    Intervals given a noteStart and a name will generate noteEnd automagically. \ 
They also get transposePitch() improvements along the way.

    KeySignature gets transposePitchFromC() which takes a pitch in C major and \ 
returns the pitch in the same scale degree in this key..

    Voices with gaps in them work way better in MusicXML. Repeat endings with \ 
multiple numbers like 1,2 r/t with musicxml (JTW)

    TSV files which encode harmonic analysis can now be parsed (Thanks Mark Gotham)

    Humdrum harm spines parse now, giving another way of encoding harmonic \ 
analysis. (Thanks Néstor Nápoles López)

    MIDI refactor: easier to subclass and extend and with many docs -- keeps a \ 
clear distinction between strings and bytes. MIDI values are all Enum classes \ 
(but IntEnums so they compare well with pure numbers)

    StripTies works much better thanks to JTW -- and does not filter out \ 
non-Notes anymore (technically an incompatibility, but really a bug fix). \ 
Voices, etc. don't faze .stripTies() any more. Stream.voicesToParts() also \ 
preserves more elements. Chords with some notes tied and some don't no longer \ 
get merged. Note that stripTies retainContainers defaults to True now, because \ 
getting the opposite behavior is as easy as a .flat

    Internal but important: lots of parts of music21 code that used \ 
abbreviations now spell out the whole word. This is important for our friends \ 
using screen readers. While music21 will (for historical/compatibility reasons) \ 
still use camelCase for all method names, attribute names, etc., internal \ 
variables may now use underscore_case which helps with screen readers.

    Stream().write('mxl') will write compressed musicxml (JTW). Or write('...', \ 
format='musicxml', compress=True)

    Improvements to VoiceLeadingQuartets (thanks Ryaan Ahmed), including finding \ 
parallel intervals with octave displacement. voiceCrossing and voiceOverlap \ 
detection.

    Substantial improvements to RomanText: see \ 
https://dmitri.mycpanel.princeton.edu/romantext.pdf

    RomanNumerals can specify how they represent ^6 and ^7 in minor with \ 
sixthMinor and seventhMinor keywords)

    OMR fixers can recognize Turns and other ornaments. More merging here to \ 
come. Thanks Janelle Sands!

    Substantial improvements to beaming routines and tests (thanks Almog Cohen!)

    Keys now have .deriveByDegree() like Scales, so "What minor key has \ 
scale degree 3 as B-flat?" can easily be answered.

    Improvements to dotted tuplets (Almog Cohen)

    Chord.name/fullName now gives better names for common chords like \ 
Major/Minor triads -- no longer relies entirely on chord.tables. But even there \ 
many improvements and spelling corrections.

    Chords expose .notes to get at the notes that make up a chord, in a \ 
different way than Chord[0] or for n in Chord -- I'm still an old Perl guy, \ 
sometimes There's More Than One Way to Do It, and this way makes some things \ 
conceptually much easier and faster.

    More Bach Chorale fixes from Doctor Schmidt (thanks!)

    Stream.replace(recurse=True) finally works!

    StringIndication, FretIndication work in musicxml (thanks Peter Mitrano)

    For those who are adventurous -- intervalNetworks are now exposed on scales.

    prebase.ProtoM21Object -- an idea ported back from music21j: nearly every \ 
object in music21, including all Music21Objects, inherits from this \ 
super-lightweight base class which allows for querying classes and giving \ 
consistent representations. It makes working in music21 a lot more fun.

Incompatible Changes

    Stream filters now return a new StreamIterator. So old code like:

s = stream.Stream()
sIter = s.iter
sIter.getElementsByClass('Chord')
list(sIter)

should now be written as:

s = stream.Stream()
sIter = s.iter
sIter2 = sIter.getElementsByClass('Chord')
list(sIter2)

For most people using filters within a for-loop, nothing will appear to have changed.

    if element in stream now only returns True if the element is actually in the \ 
Stream, not if element is equal to something in the Stream. This is not normal \ 
Python behavior for __contains__ but it is something music21 users have counted \ 
on for a decade, and now it is assured.

    MIDI has been completely refactored, so if you are mucking with MIDI \ 
internals, it's going to be completely different. If you're just using \ 
converter.parse and .write('midi') it won't have changed much.

Also

    Setting a pitch's accidental to a number is deprecated and to be removed \ 
soon. use b = pitch.Pitch('B4'); b.accidental = pitch.Accidental(-1).
    some long deprecated functions removed, such as Stream.restoreActiveSites, \ 
Stream. _yieldReverseUpwardsSearch, common.standardDeviation (use \ 
statistics.stdev instead).
    Chord sort methods no longer return the chord itself if inPlace=True
    interval.convertSemitoneToSpecifierGenericMicrotone, \ 
convertSemitoneToSpecifierGeneric now return a Specifier Enum as their first \ 
value
    Spelling corrections that are technically incompatible: Interval.perfectable \ 
replaces typo Interval.prefectable. Appoggiatura is spelled correctly with \ 
two-gs everywhere it's used (JTW)
    stripTies(retainContainers=True) is now the default.
    Half-diminished chords have ø7 etc. as their default representation.
    MIDI.intsToHexString has become MIDI.intsToHexBytes which does what is says \ 
it does.

Small Changes/Bugs squashed:

    A malformed spanner in musicxml will no longer crash parsing.
    Tuplets are equal if their durations are equal. Better docs for duration \ 
equality.
    contextSites, next, previous, and getContextByClass have a \ 
priorityTargetOnly or activeSiteOnly keyword for searching activeSite only. \ 
Speed!
    From music21.X import * works much more reliably.
    Bugs fixed in feature extraction of keys.
    serial allows "P" or "T" to be used for transpositions
    Tone-Rows give their row in the repr.
    Historical tone-rows no longer have Row in their name. For instance: \ 
serial.getHistoricalRowByName('SchoenbergOp37').matrix() -- the old form still \ 
works though.
    Feature extraction on empty streams (or ones that don't have instruments or \ 
something else) works properly (JTW)
    Feature output formats can set .ext directly, in case you need a different \ 
extension.
    viio7 can be specified as vii07
    Interval: reverse=True works properly
    subprocess.run is used instead of os.system for PNG generation. Thanks Uğur \ 
Güney. Fixes using musescore with music21 in Jupyter when spaces appear in \ 
filenames. (also thanks to Frank Zalkow)
    Better representation for many objects
    Error handling for incorrect chord abbreviation is improved. Thanks Vikram \ 
Natarajan
    Librettists and lyricists can be searched in metadata. .age() works properly \ 
for living composers.
    MIDI plays back properly in Jupyter again BUT also does not add a delay when \ 
writing out a file.
    Voice numbers in generated musicxml are now low numbers
    pitch.Accidental gets . setAttributeIndependently() in case you want \ 
something to look like a flat but only alter 0.8 semitones. (This appeared in \ 
v.5 at some point but was never announced)
    Note gets a pitchChanged() method which is called by its attached pitch \ 
anytime it changes so that caches can be used. Pitch gets an informClient() \ 
method which is called anytime the pitch itself changes. There is something \ 
similar in Chords too. This squashes a lot of bugs where pitches were changing \ 
but notes/chords/scales/etc. did not act like they had changed.
    makeAccidentals works properly in Voices (JTW)
    MIDI parsing gets more instrument objects from more places (JTW)
    zero-length objects at the end of streams were being ignored by makeNotation \ 
(JTW)
    Show formats: MuseScore 3.5 compatibility. (JTW). Preview is found by \ 
default on macOS Catalina/Big Sur -- still works for older OSes. No more 'is \ 
your doc > 999 pages?' bugs!
    Some Neo-Riemannian docs weren't showing (thanks Adam Spiers)
    Tone profiles for key analysis have been corrected. (thanks Micah Walter)
    scaleDegreeWithAlteration on Augmented 6th chords works.
    .musicxml is fully recognized as a suffix.
    Improvements to analysis.windowed (thanks Sandro Luck)
    RepeatExpander now does nothing on a score with no repeats. Before, it crashed.
    Sousa example couldn't show before (thanks David H. Gutteridge)
    Verticality.removeVerticalDissonances now works (also thanks to Gutteridge)
    Z-relation for 5Z37 (5Z17) was incorrect (thanks Rodrigo Balthar Furman for \ 
spotting this)
    Power-users who subclass Stream to be standard storage variants: \ 
Stream().coreSelfActiveSite(el) allows for subclassing what happens when an \ 
element should normally have its activeSite set to the stream.
    Lilypond output with UTF-8 works. Grace notes no longer crash Lilypond. Now \ 
that there is a 64-bit binary Mac version of Lilypond, it will not be removed \ 
from music21.
    RomanNumerals compare with each other. __eq__ logically defined.
    Modest performance improvements in sorting (Thanks Alexander Morgan)
    Documentation and test improvements and a few bugs squashed in ABC parsing.
    f-strings used throughout music21 allowing for more detailed error messages \ 
and many bugs to be detected and removed.

Deprecations

    interval.Interval.convertSpecifier() deprecated. use parseSpecifier instead.
    Humdrum parseData() and parseFile() are deprecated. use the general \ 
converter.parse() instead.
    .editorial.misc is deprecated, just stick whatever you want on the \ 
.editorial object itself.

Gratitude

As always, I want to thank MIT, the NEH, and the Seaver Institute for supporting \ 
music21 over the years along with the community of developers who use and give \ 
back to music21.