I need 1 Paid Leave to allocate each month to the employee. How can i set up that?

but i need to allocate leaves by monthly.eg:

in october i allocate 2 leaves for all employees

in august, there is no allocation.

but now the employee can able to take 2 leaves in august,that is the error,i need there is no leave in august,only in october they take 2 leaves.

so please find a solution

i added the py file

from osv import osv,fields
from openerp.tools.translate import _

class leave_info(osv.osv):
   
   # _name='leave.info'
    _inherit='hr.holidays'
   
       
    def button_generate(self,cr,uid,ids,context=None):
        dummy, view_id = self.pool.get('ir.model.data').get_object_reference(cr, uid,'hr_holidays', 'allocation_leave_new')
        inv = self.browse(cr, uid, ids[0], context=context)
        return {
            'name':_("Leave Allocation"),
            'view_mode': 'form',
            'view_id': view_id,
            'view_type': 'form',
            'res_model': 'hr.holidays',
            'type': 'ir.actions.act_window',
            'nodestroy': True,
            'domain': '[]',
            'context': None
                }
    
leave_info()