If the plist type is none, return None.
If the plist type is none, return None.

libimobiledevice/libplist,Tatsh/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,Tatsh/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,Tatsh/libplist,libimobiledevice-win32/libplist,Tatsh/libplist