+ if not key:
+ return None
+ fifths_elm = key.get_maybe_exist_named_child ('fifths')
+ if fifths_elm:
+ mode_node = key.get_maybe_exist_named_child ('mode')
+ mode = None
+ if mode_node:
+ mode = mode_node.get_text ()
+ if not mode or mode == '':
+ mode = 'major'
+ fifths = int (fifths_elm.get_text ())
+ # TODO: Shall we try to convert the key-octave and the cancel, too?
+ return (fifths, mode)
+ else:
+ alterations = []
+ current_step = 0
+ for i in key.get_all_children ():
+ if isinstance (i, KeyStep):
+ current_step = i.get_text ().strip ()
+ elif isinstance (i, KeyAlter):
+ alterations.append ([current_step, interpret_alter_element (i)])
+ elif isinstance (i, KeyOctave):
+ nr = -1
+ if hasattr (i, 'number'):
+ nr = int (i.number)
+ if (nr > 0) and (nr <= len (alterations)):
+ # MusicXML Octave 4 is middle C -> shift to 0
+ alterations[nr-1].append (int (i.get_text ())-4)
+ else:
+ i.message (_ ("Key alteration octave given for a "
+ "non-existing alteration nr. %s, available numbers: %s!") % (nr, len(alterations)))
+ return alterations
+
+ def get_transposition (self):
+ return self.get_named_attribute ('transpose')
+
+class KeyAlter (Music_xml_node):
+ pass
+class KeyStep (Music_xml_node):
+ pass
+class KeyOctave (Music_xml_node):
+ pass