[musicxml2ly] missing <voice>-element in chorded note leads to unwanted additional staff

[pls]

A <note>-element containing a <chord/>- and a <staff>-element but no 
<voice>-element causes an additional empty staff above the defined one.

Tiny example:

missing_voice-element_in_a_chorded_note_leads_to_empty_second_staff.xml
Description: application/xml

(unwanted) result:

The wrong MusicXML-markup was caused by Sibelius 7.0.0.

In this case musicxml2ly puts the chorded note without a <voice>-element in an 
own voice (PartPOneVoiceNone) instead of placing the notes in a chord construct 
(< a' c''>1) in the same voice. She also surrounds the \context Staff block by 
an additional \new Staff block which causes the additional staff.

musicxml2ly should be taught to be tolerant and automatically assign notes 
containing <chord/>-elements to the voice of the first note of the chord. (This 
first note does not contain a <chord/>-element.)

hth
patrick