you can use groups keywords/attribute in python as well as in xml.

some thing Like in xml [/account/account_invoice_view.xml]:

 <field domain="[('company_id', '=', company_id), ('type', '=', 'payable')]"
                                name="account_id" groups="account.group_account_user"/>

some thing Like in .py [/addons/account/partner.py]:

'total_invoiced': fields.function(_invoice_total, string="Total Invoiced", 
                                    type='float', 
                                    groups='account.group_account_invoice')