m_id is tokens type property inside "data" propertysheet in a ZClass. This Python Script works fine when called on the ZClass. It changes the value of m_id property. new_m_id=[777,888,999] context.propertysheets.data.manage_changeProperties(m_id=new_m_id) However, the following script does not change the value of m_id property. It runs as if everything is ok. It finds correct instance using "title", the x[0].m_id and x[0].title show correct values, but the "line x[0].manage_changeProperties(m_id=new_m_id)" has no effect whatsoever. x=context.Catalog_Org(title="aaa") print x[0].m_id print x[0].title new_m_id=[999,888,777] x[0].manage_changeProperties(m_id=new_m_id) print x[0].m_id I tried to call "x[0].propertysheets.data.manage_changeProperties(m_id=new_m_id)", but it fails with Error Type: AttributeError, Error Value: data -- Milos Prudek