Avoid testing truth value of ElementTree.Element

music21/musicxml/m21ToXml.py

@@ -1077,7 +1077,7 @@ def pageLayoutToXmlPrint(self, pageLayout, mxPrintIn=None):
         setb(pageLayout, mxPrint, 'page-number')
 
         mxPageLayout = self.pageLayoutToXmlPageLayout(pageLayout)
-        if mxPageLayout:
+        if len(mxPageLayout):
             mxPrint.append(mxPageLayout)
 
         if mxPrintIn is None:
@@ -1104,7 +1104,7 @@ def pageLayoutToXmlPageLayout(self, pageLayout, mxPageLayoutIn=None):
         mxPageMargins = Element('page-margins')
         for direction in ('left', 'right', 'top', 'bottom'):
             seta(pageLayout, mxPageMargins, direction + '-margin')
-        if mxPageMargins:
+        if len(mxPageMargins):
             mxPageLayout.append(mxPageMargins)
 
         if mxPageLayoutIn is None:
@@ -1158,7 +1158,7 @@ def systemLayoutToXmlPrint(self, systemLayout, mxPrintIn=None):
 
         mxSystemLayout = Element('system-layout')
         self.systemLayoutToXmlSystemLayout(systemLayout, mxSystemLayout)
-        if mxSystemLayout:
+        if len(mxSystemLayout):
             mxPrint.append(mxSystemLayout)
 
         if mxPrintIn is None:
@@ -1204,7 +1204,7 @@ def systemLayoutToXmlSystemLayout(self, systemLayout, mxSystemLayoutIn=None):
         for direction in ('top', 'bottom', 'left', 'right'):
             seta(systemLayout, mxSystemMargins, direction + '-margin')
 
-        if mxSystemMargins:
+        if len(mxSystemMargins):
             mxSystemLayout.append(mxSystemMargins)
 
         seta(systemLayout, mxSystemLayout, 'system-distance', 'distance')
@@ -2505,7 +2505,7 @@ def setTitles(self) -> None:
                 firstTitleFound = titles[0]
             mxWorkTitle = SubElement(mxWork, 'work-title')
             mxWorkTitle.text = str(titles[0])
-        if mxWork:
+        if len(mxWork):
             mxScoreHeader.append(mxWork)
 
         movementNumbers: tuple[metadata.Text, ...] = mdObj['movementNumber']
@@ -4942,7 +4942,7 @@ def noteToNotations(
         for x in (mxArticulations,
                   mxTechnicalMark,
                   mxOrnaments):
-            if x:
+            if x is not None:
                 notations.append(x)
 
         # TODO: dynamics in notations

music21/musicxml/partStaffExporter.py

@@ -575,10 +575,9 @@ def isMultiAttribute(m21Class: type[M21ObjType],
             # Initial PartStaff in group: find earliest mxAttributes, set clef #1 and <staves>
             if initialPartStaffRoot is None:
                 initialPartStaffRoot = self.getRootForPartStaff(ps)
-                mxAttributes = initialPartStaffRoot.find('measure/attributes')
-                clef1: Element | None = mxAttributes.find('clef') if mxAttributes else None
-                if clef1 is not None:
-                    clef1.set('number', '1')
+                if (mxAttributes := initialPartStaffRoot.find('measure/attributes')) is not None:
+                    if (clef1 := mxAttributes.find('clef')) is not None:
+                        clef1.set('number', '1')
 
                 mxStaves = Element('staves')
                 mxStaves.text = str(len(group))
@@ -591,11 +590,11 @@ def isMultiAttribute(m21Class: type[M21ObjType],
 
                 if multiKey and mxAttributes is not None:
                     key1 = mxAttributes.find('key')
-                    if key1:
+                    if key1 is not None:
                         key1.set('number', '1')
                 if multiMeter and mxAttributes is not None:
                     meter1 = mxAttributes.find('time')
-                    if meter1:
+                    if meter1 is not None:
                         meter1.set('number', '1')
 
             # Subsequent PartStaffs in group: set additional clefs on mxAttributes
@@ -631,19 +630,15 @@ def isMultiAttribute(m21Class: type[M21ObjType],
                     )
 
                 if multiMeter:
-                    oldMeter: Element | None = thisPartStaffRoot.find(
-                        'measure/attributes/time'
-                    )
-                    if oldMeter:
+                    if (oldMeter := thisPartStaffRoot.find('measure/attributes/time')) is not None:
                         oldMeter.set('number', str(staffNumber))
                         helpers.insertBeforeElements(
                             mxAttributes,
                             oldMeter,
                             tagList=['staves']
                         )
                 if multiKey:
-                    oldKey: Element | None = thisPartStaffRoot.find('measure/attributes/key')
-                    if oldKey:
+                    if (oldKey := thisPartStaffRoot.find('measure/attributes/key')) is not None:
                         oldKey.set('number', str(staffNumber))
                         helpers.insertBeforeElements(
                             mxAttributes,

music21/musicxml/xmlToM21.py

@@ -2844,7 +2844,7 @@ def xmlToChord(self, mxNoteList: list[ET.Element]) -> chord.ChordBase:
             notes.append(self.xmlToSimpleNote(mxNote, freeSpanners=False))
 
         c: chord.ChordBase
-        if any(mxNote.find('unpitched') for mxNote in mxNoteList):
+        if any(mxNote.find('unpitched') is not None for mxNote in mxNoteList):
             c = percussion.PercussionChord(notes)
         else:
             c = chord.Chord(notes)  # type: ignore  # they are all Notes.