问引用optionMenu的Maya Python返回为不存在

EN

import maya.cmds as maya

def testWin():
    winName = maya.window(title="test", rtf = True, mxb = False)
    maya.columnLayout()

    maya.button(label = "run test", c = "test()")
    shapeMenu = maya.optionMenu( label='Shape Menu', changeCommand="test()" )
    maya.menuItem( label='Circle' )
    maya.menuItem( label='Square' )
    maya.menuItem( label='Triangle' )

    maya.showWindow(winName)

testWin()

def test():
    sel = maya.ls(type = "joint", sl=True)
    if not sel:
        print "select at least 1 JOINT"

    else:
        new_pos = maya.xform(q=True, t=True, ws=True)
        new_rot = maya.xform(q=True, rotation=True, ws=True)
        shape = maya.optionMenu("Shape Menu", q = True, value = True)

        if shape == "Circle":
            new_control = maya.circle(center = new_pos)
        elif shape == "Square":
            new_control = maya.nurbsSquare(center = new_pos)
        elif shape == "Triangle":
            new_control = maya.circle(center = new_pos, degree = 1, sections = 3)