I am extending the openerp payroll module for our needs, but we have to define many other models to achieve our purpose. In python code of salary rule we can fetch some objects like - contract, payslip, employee, rules, categories etc. with a field name. Currently the process is contract.wage grabs the basic salary from the contract in the python code of salary rule. I want to achieve the same functionality for some objects, like - my_object.my_field . How can achieve this?

Any suggestions will be greatly appreciated! Thanks in advance.