diff --git a/addons/account/account_financial_report.py b/addons/account/account_financial_report.py
index 28b5e08dc99..1d9a4a794eb 100644
--- a/addons/account/account_financial_report.py
+++ b/addons/account/account_financial_report.py
@@ -39,6 +39,8 @@ class account_financial_report(osv.osv):
     _description = "Account Report"
 
     def _get_level(self, cr, uid, ids, field_name, arg, context=None):
+        '''Returns a dictionary with key=the ID of a record and value = the level of this  
+            record in the tree structure.'''
         res = {}
         for report in self.browse(cr, uid, ids, context=context):
             level = 0
@@ -48,6 +50,8 @@ class account_financial_report(osv.osv):
         return res
 
     def _get_children_by_order(self, cr, uid, ids, context=None):
+        '''returns a dictionary with the key= the ID of a record and value = all its children,
+           computed recursively, and sorted by sequence. Ready for the printing'''
         res = []
         for id in ids:
             res.append(id)
@@ -56,6 +60,12 @@ class account_financial_report(osv.osv):
         return res
 
     def _get_balance(self, cr, uid, ids, field_names, args, context=None):
+        '''returns a dictionary with key=the ID of a record and value=the balance amount 
+           computed for this record. If the record is of type :
+               'accounts' : it's the sum of the linked accounts
+               'account_type' : it's the sum of leaf accoutns with such an account_type
+               'account_report' : it's the amount of the related report
+               'sum' : it's the sum of the children of this record (aka a 'view' record)'''
         account_obj = self.pool.get('account.account')
         res = {}
         for report in self.browse(cr, uid, ids, context=context):