IndexError: list index out of range need a help  When I click on def  check_eligibility function error is occurs

_name='hr.employee'
     _inherit=['hr.employee','mail.thread']

     _columns={
              'date_of_join' :fields.date('Date of Join',required=True),
              'current_date':fields.date('Applied date',require=True),
              'eligible_details':fields.char('Eligibility Details'),
              'visaexpiry_date':fields.date('Visa Expiry Date'),
               'residence_expiry_date':fields.date('Residence Expiry',required=True),
               'work_permit_date':fields.date('Work Permit'),
               'insurance_expiry_date':fields.date('Insurance date'),
               'license_date':fields.date('License date',required=True)
                             }

def  check_eligibility(self,cr,uid,ids,context=None):
         day_obj=self.read(cr,uid,ids,['date_of_join','current_date'],context=context)
     print "day_obj#############################",day_obj
         
         calc_vacation=self.pool.get('scheme.type.info').read(cr,uid,ids,['interval','criteria','scheme_id'],context=context)
     print "day_obj#############################",calc_vacation
         
         
         dateformat="%Y-%m-%d"
         d1=datetime.strptime(day_obj[0]['date_of_join'],dateformat)
         d2=datetime.strptime(day_obj[0]['current_date'],dateformat)
         v1=d2-d1
         
         total_days=v1.days
       
         if total_days<=calc_vacation[0]['interval'] and calc_vacation[0]['scheme_id']==1 :
             msg=calc_vacation[0]['criteria']
         elif total_days<=calc_vacation[0]['interval'] and calc_vacation[0]['scheme_id']==2:
              msg=calc_vacation[0]['criteria']
         else:
             msg="You are not eligible"
         vals={
               'eligible_details':msg
               }
         self.write(cr,uid,ids,vals)
        
         return True

     
class scheme_type_info(osv.osv):
    
    _name='scheme.type.info'
    
    _columns={
              'scheme_id':fields.integer('Scheme Type',required=True,size=50),
              'interval':fields.integer('interval type ',required=True,size=64),
              'criteria':fields.text('vacation criteria',required=True,size=50),
              'active':fields.boolean('Active')
              }
    
scheme_type_info()

---------------------

This is the values inside day_obj some time it have not  values , some time it have

day_obj############################# [{'current_date': '2014-06-19', 'date_of_join': '2014-06-04', 'id': 7, 'resource_id': 7}]
day_obj############################# []

day_obj############################# [{'current_date': '2019-06-27', 'date_of_join': '2014-06-11', 'id': 2, 'resource_id': 2}]
day_obj############################# [{'interval': 300, 'id': 2, 'scheme_id': 2, 'criteria': u'tfggt'}]