Hey How I can print multiple report on one Button click here is some sample which I was trying but it didn't succeeded,

# Function : Print A5 receipt
@api.multi
def print_thermal_reciept_imaging(self):
    return self.env.ref('gts_hms_single_payment_panel.single_window_thermal_receipt_imaging').report_action(self)

@api.multi
def print_thermal_reciept_labtest(self):
    return self.env.ref('gts_hms_single_payment_panel.single_window_thermal_receipt_labtest').report_action(self)

@api.multi
def print_thermal_reciept_other_procedure(self):
    return self.env.ref('gts_hms_single_payment_panel.single_window_thermal_receipt_other_procedure').report_action(self)

@api.multi
def print_thermal_reciept_surgery(self):
    return self.env.ref('gts_hms_single_payment_panel.single_window_thermal_receipt_surgery').report_action(self)

@api.multi
def print_thermal_reciept(self):
    return self.print_thermal_reciept_imaging(), self.print_thermal_reciept_labtest(), self.print_thermal_reciept_other_procedure(), self.print_thermal_reciept_surgery()