A = Class('virtual2::A', 'virtual2.h')
set_policy(A.make_new, return_value_policy(manage_new_object))
B = Class('virtual2::B', 'virtual2.h')
set_policy(B.make_new, return_value_policy(manage_new_object))
Function('virtual2::call_fs', 'virtual2.h')
Function('virtual2::call_f', 'virtual2.h')