IN odoo 10
class HrPayslipMultiCompany(models.Model):
_inherit = 'hr.payslip.run'
salary_date = fields.Date("Salary Date")
<xpath expr="//field[@name='journal_id']" position="after">
<field name="salary_date"/>
</xpath>
salary_d = self.env['hr.payslip.run'].search([('salary_date', '!=', False)])
print (salary_d)
output:hr.payslip.run(5,)