AuiManager ,left and right panel have same size

i want to add tow panels on AuiManager ,the proprtion is 1:1

but when i create it with below code like this:

self.mgr.AddPane(leftpanel, wx.aui.AuiPaneInfo().Center()
self.mgr.AddPane(rightpanel, wx.aui.AuiPaneInfo().Right()

the proprtion is 5:1

how to Initialize the proportion ?