+class ChordModification:
+ def __init__ (self):
+ self.alteration = 0
+ self.step = 0
+ self.type = 0
+ def ly_expression (self):
+ if self.type:
+ val = {1: ".", -1: "^" }.get (self.type, "")
+ val += "%s" % self.step
+ val += {1: "+", -1: "-"}.get (self.alteration, "")
+ return val
+ else:
+ return ''
+