diff --git a/ZAbsences.py b/ZAbsences.py
index 1bdd11b7a..d450d09f1 100644
--- a/ZAbsences.py
+++ b/ZAbsences.py
@@ -45,17 +45,19 @@ L'API de plus bas niveau est en gros:
 """
 
 import urllib
+import datetime
+import jaxml
 
+# ---------------
 from sco_zope import *
 
 # ---------------
-
-from notesdb import *
+import sco_utils as scu
+import notesdb
 from notes_log import log
 from scolog import logdb
-from sco_utils import *
-
-# import notes_users
+from sco_permissions import ScoAbsAddBillet, ScoAbsChange, ScoView
+from sco_exceptions import ScoValueError, ScoInvalidDateError
 from TrivialFormulator import TrivialFormulator, TF
 from gen_tables import GenTable
 import scolars
@@ -201,7 +203,7 @@ class ddmmyyyy:
             return self.prev(self.weekday)
 
     def __cmp__(self, other):
-        """return a negative integer if self < other, 
+        """return a negative integer if self < other,
         zero if self == other, a positive integer if self > other"""
         return int(self.time - other.time)
 
@@ -356,7 +358,7 @@ class ZAbsences(
         estjust = _toboolean(estjust)
         matin = _toboolean(matin)
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             "insert into absences (etudid,jour,estabs,estjust,matin,description, moduleimpl_id) values (%(etudid)s, %(jour)s, TRUE, %(estjust)s, %(matin)s, %(description)s, %(moduleimpl_id)s )",
             vars(),
@@ -380,7 +382,7 @@ class ZAbsences(
             raise ScoValueError("date justificatif trop loin dans le futur !")
         matin = _toboolean(matin)
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             "insert into absences (etudid,jour,estabs,estjust,matin, description) values (%(etudid)s,%(jour)s, FALSE, TRUE, %(matin)s, %(description)s )",
             vars(),
@@ -402,7 +404,7 @@ class ZAbsences(
         # unpublished
         matin = _toboolean(matin)
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         req = "delete from absences where jour=%(jour)s and matin=%(matin)s and etudid=%(etudid)s and estabs"
         if moduleimpl_id:
             req += " and moduleimpl_id=%(moduleimpl_id)s"
@@ -423,7 +425,7 @@ class ZAbsences(
         # unpublished
         matin = _toboolean(matin)
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             "delete from absences where jour=%(jour)s and matin=%(matin)s and etudid=%(etudid)s and ESTJUST AND NOT ESTABS",
             vars(),
@@ -450,7 +452,7 @@ class ZAbsences(
     #     """
     #     # unpublished
     #     cnx = self.GetDBConnexion()
-    #     cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+    #     cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
     #     # supr les absences non justifiees
     #     cursor.execute("delete from absences where etudid=%(etudid)s and (not estjust) and moduleimpl_id=(moduleimpl_id)s and jour BETWEEN %(datedebut)s AND %(datefin)s",
     #                    vars() )
@@ -487,7 +489,7 @@ class ZAbsences(
                 self._AnnuleAbsence(etudid, jour, matin, moduleimpl_id, REQUEST)
             return
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         # supr les absences non justifiees
         for date in dates:
             cursor.execute(
@@ -534,7 +536,7 @@ class ZAbsences(
         else:
             modul = ""
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             """SELECT COUNT(*) AS NbAbs FROM (
     SELECT DISTINCT A.JOUR, A.MATIN
@@ -565,7 +567,7 @@ class ZAbsences(
         else:
             modul = ""
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             """SELECT COUNT(*) AS NbAbsJust FROM (
   SELECT DISTINCT A.JOUR, A.MATIN
@@ -588,7 +590,7 @@ class ZAbsences(
     def _ListeAbsDate(self, etudid, beg_date, end_date):
         # Liste des absences et justifs entre deux dates
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             """SELECT jour, matin, estabs, estjust, description FROM ABSENCES A 
      WHERE A.ETUDID = %(etudid)s
@@ -598,7 +600,6 @@ class ZAbsences(
             vars(),
         )
         Abs = cursor.dictfetchall()
-        # log('ListeAbsDate: abs=%s' % Abs)
         # remove duplicates
         A = {}  # { (jour, matin) : abs }
         for a in Abs:
@@ -625,7 +626,6 @@ class ZAbsences(
         # sort
         R = A.values()
         R.sort(key=lambda x: (x["begin"]))
-        # log('R=%s' % R)
         return R
 
     security.declareProtected(ScoView, "ListeAbsJust")
@@ -633,7 +633,7 @@ class ZAbsences(
     def ListeAbsJust(self, etudid, datedebut):
         "Liste des absences justifiees (par ordre chronologique)"
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             """SELECT DISTINCT A.ETUDID, A.JOUR, A.MATIN FROM ABSENCES A, ABSENCES B
  WHERE A.ETUDID = %(etudid)s
@@ -654,7 +654,7 @@ class ZAbsences(
     def ListeAbsNonJust(self, etudid, datedebut):
         "Liste des absences NON justifiees (par ordre chronologique)"
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         cursor.execute(
             """SELECT ETUDID, JOUR, MATIN FROM ABSENCES A 
     WHERE A.ETUDID = %(etudid)s
@@ -680,7 +680,7 @@ class ZAbsences(
         Si only_no_abs: seulement les justificatifs correspondant aux jours sans absences relevées.
         """
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         req = """SELECT DISTINCT ETUDID, JOUR, MATIN FROM ABSENCES A
  WHERE A.ETUDID = %(etudid)s
  AND A.ESTJUST
@@ -704,7 +704,7 @@ class ZAbsences(
         "Description associee a l'absence"
         if not cursor:
             cnx = self.GetDBConnexion()
-            cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+            cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         a = a.copy()
         # a['jour'] = a['jour'].date()
         if a["matin"]:  # devrait etre booleen... :-(
@@ -732,7 +732,6 @@ class ZAbsences(
 
         if desc:
             return "(%s) %s" % (desc, module)
-            return desc
         if module:
             return module
         return ""
@@ -745,7 +744,7 @@ class ZAbsences(
         is_just: idem
         """
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         req = """SELECT DISTINCT etudid, jour, matin FROM ABSENCES A 
     WHERE A.jour = %(date)s
     """
@@ -769,7 +768,7 @@ class ZAbsences(
     def ListeAbsNonJustJour(self, date, am=True, pm=True):
         "Liste des absences non justifiees ce jour"
         cnx = self.GetDBConnexion()
-        cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+        cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
         reqa = ""
         if not am:
             reqa += " AND NOT matin "
@@ -849,7 +848,7 @@ class ZAbsences(
     def CalSelectWeek(self, year=None, REQUEST=None):
         "display calendar allowing week selection"
         if not year:
-            year = AnneeScolaire(REQUEST)
+            year = scu.AnneeScolaire(REQUEST)
         sems = sco_formsemestre.do_formsemestre_list(self)
         if not sems:
             js = ""
@@ -886,10 +885,9 @@ class ZAbsences(
     security.declareProtected(ScoView, "ListMondays")
 
     def ListMondays(self, year=None, REQUEST=None):
-        """return list of mondays (ISO dates), from september to june
-        """
+        """return list of mondays (ISO dates), from september to june"""
         if not year:
-            year = AnneeScolaire(REQUEST)
+            year = scu.AnneeScolaire(REQUEST)
         d = ddmmyyyy("1/9/%d" % year, work_saturday=self.is_work_saturday())
         while d.weekday != 0:
             d = d.next()
@@ -934,7 +932,7 @@ class ZAbsences(
     ):
         "Saisie hebdomadaire des absences"
         if not moduleimpl_id:
-            moduleimp_id = None
+            moduleimpl_id = None
 
         groups_infos = sco_groups_view.DisplayedGroupsInfos(
             self, group_ids, REQUEST=REQUEST
@@ -963,10 +961,10 @@ class ZAbsences(
         )[0]
 
         # calcule dates jours de cette semaine
-        datessem = [DateDMYtoISO(datelundi)]
-        for jour in self.day_names()[1:]:
+        # liste de dates iso "yyyy-mm-dd"
+        datessem = [notesdb.DateDMYtoISO(datelundi)]
+        for _ in self.day_names()[1:]:
             datessem.append(self.NextISODay(datessem[-1]))
-
         #
         if groups_infos.tous_les_etuds_du_sem:
             gr_tit = "en"
@@ -1044,9 +1042,7 @@ class ZAbsences(
             % {"menu_module": menu_module, "url": base_url, "sel": sel}
         )
 
-        H += self._gen_form_saisie_groupe(
-            etuds, self.day_names(), datessem, destination, None, moduleimpl_id
-        )
+        H += self._gen_form_saisie_groupe(etuds, datessem, destination, moduleimpl_id)
 
         H.append(self.sco_footer(REQUEST))
         return "\n".join(H)
@@ -1063,8 +1059,7 @@ class ZAbsences(
         moduleimpl_id=None,
         REQUEST=None,
     ):
-        """Saisie des absences sur une journée sur un semestre (ou intervalle de dates) entier
-        """
+        """Saisie des absences sur une journée sur un semestre (ou intervalle de dates) entier"""
         # log('SignaleAbsenceGrSemestre: moduleimpl_id=%s destination=%s' % (moduleimpl_id, destination))
         groups_infos = sco_groups_view.DisplayedGroupsInfos(
             self, group_ids, REQUEST=REQUEST
@@ -1083,15 +1078,12 @@ class ZAbsences(
         ]
 
         if not moduleimpl_id:
-            moduleimp_id = None
-        base_url_noweeks = (
-            "SignaleAbsenceGrSemestre?datedebut=%s&amp;datefin=%s&amp;%s&amp;destination=%s"
-            % (
-                datedebut,
-                datefin,
-                groups_infos.groups_query_args,
-                urllib.quote(destination),
-            )
+            moduleimpl_id = None
+        base_url_noweeks = "SignaleAbsenceGrSemestre?datedebut=%s&amp;datefin=%s&amp;%s&amp;destination=%s" % (
+            datedebut,
+            datefin,
+            groups_infos.groups_query_args,
+            urllib.quote(destination),
         )
         base_url = (
             base_url_noweeks + "&amp;nbweeks=%s" % nbweeks
@@ -1139,7 +1131,6 @@ class ZAbsences(
         if moduleimpl_id:
             url_link_semaines += "&amp;moduleimpl_id=" + moduleimpl_id
         #
-        colnames = [str(x) for x in dates]
         dates = [x.ISO() for x in dates]
         dayname = self.day_names()[jourdebut.weekday]
 
@@ -1147,9 +1138,9 @@ class ZAbsences(
             gr_tit = "en"
         else:
             if len(groups_infos.group_ids) > 1:
-                p = "des groupes"
+                p = "des groupes "
             else:
-                p = "du groupe"
+                p = "du groupe "
             gr_tit = (
                 p + '<span class="fontred">' + groups_infos.groups_titles + "</span>"
             )
@@ -1217,15 +1208,18 @@ class ZAbsences(
                 % {"menu_module": menu_module, "url": base_url, "sel": sel}
             )
 
-        H += self._gen_form_saisie_groupe(
-            etuds, colnames, dates, destination, dayname, moduleimpl_id
-        )
+        H += self._gen_form_saisie_groupe(etuds, dates, destination, moduleimpl_id)
         H.append(self.sco_footer(REQUEST))
         return "\n".join(H)
 
-    def _gen_form_saisie_groupe(
-        self, etuds, colnames, dates, destination="", dayname="", moduleimpl_id=None
-    ):
+    def _gen_form_saisie_groupe(self, etuds, dates, destination="", moduleimpl_id=None):
+        """Formulaire saisie absences
+
+        Args:
+            etuds: liste des étudiants
+            dates: liste de dates iso, par exemple: [ '2020-12-24', ... ]
+            moduleimpl_id: optionnel, module concerné.
+        """
         H = [
             """
         <script type="text/javascript">
@@ -1252,25 +1246,29 @@ class ZAbsences(
         """
             % len(etuds)
         ]
+        # Dates
+        odates = [datetime.date(*[int(x) for x in d.split("-")]) for d in dates]
         # Titres colonnes
-        if dayname:
-            for jour in colnames:
-                H.append(
-                    '<th colspan="2" width="100px" style="padding-left: 5px; padding-right: 5px;">'
-                    + dayname
-                    + "</th>"
-                )
-            H.append("</tr><tr><td>&nbsp;</td>")
-
-        for jour in colnames:
+        noms_jours = []  # eg [ "Lundi", "mardi", "Samedi", ... ]
+        jn = self.day_names()
+        for d in odates:
+            idx_jour = d.weekday()
+            noms_jours.append(jn[idx_jour])
+        for jour in noms_jours:
             H.append(
                 '<th colspan="2" width="100px" style="padding-left: 5px; padding-right: 5px;">'
                 + jour
                 + "</th>"
             )
-
         H.append("</tr><tr><td>&nbsp;</td>")
-        H.append("<th>AM</th><th>PM</th>" * len(colnames))
+        for d in odates:
+            H.append(
+                '<th colspan="2" width="100px" style="padding-left: 5px; padding-right: 5px;">'
+                + d.strftime("%d/%m/%Y")
+                + "</th>"
+            )
+        H.append("</tr><tr><td>&nbsp;</td>")
+        H.append("<th>AM</th><th>PM</th>" * len(dates))
         H.append("</tr>")
         #
         if not etuds:
@@ -1373,14 +1371,13 @@ class ZAbsences(
         absjust_only=0,
         REQUEST=None,
     ):
-        """Tables des absences justifiees et non justifiees d'un étudiant sur l'année en cours
-        """
+        """Tables des absences justifiees et non justifiees d'un étudiant sur l'année en cours"""
         absjust = self.ListeAbsJust(etudid=etudid, datedebut=datedebut)
         absnonjust = self.ListeAbsNonJust(etudid=etudid, datedebut=datedebut)
         # examens ces jours là ?
         if with_evals:
             cnx = self.GetDBConnexion()
-            cursor = cnx.cursor(cursor_factory=ScoDocCursor)
+            cursor = cnx.cursor(cursor_factory=notesdb.ScoDocCursor)
             for a in absnonjust + absjust:
                 cursor.execute(
                     """select eval.*
@@ -1499,10 +1496,9 @@ class ZAbsences(
         format="html",
         REQUEST=None,
     ):
-        """Liste les absences de groupes
-        """
-        datedebut = DateDMYtoISO(debut)
-        datefin = DateDMYtoISO(fin)
+        """Liste les absences de groupes"""
+        datedebut = notesdb.DateDMYtoISO(debut)
+        datefin = notesdb.DateDMYtoISO(fin)
         # Informations sur les groupes à afficher:
         groups_infos = sco_groups_view.DisplayedGroupsInfos(
             self, group_ids, REQUEST=REQUEST
@@ -1603,7 +1599,7 @@ class ZAbsences(
             base_url="%s&amp;formsemestre_id=%s&amp;debut=%s&amp;fin=%s"
             % (groups_infos.base_url, formsemestre_id, debut, fin),
             filename="etat_abs_"
-            + make_filename(
+            + scu.make_filename(
                 "%s de %s" % (groups_infos.groups_filename, sem["titreannee"])
             ),
             caption=title,
@@ -1632,26 +1628,20 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
     def EtatAbsencesDate(
         self, group_ids=[], date=None, REQUEST=None  # list of groups to display
     ):
-        """Etat des absences pour un groupe à une date donnée
-        """
+        """Etat des absences pour un groupe à une date donnée"""
         # Informations sur les groupes à afficher:
         groups_infos = sco_groups_view.DisplayedGroupsInfos(
             self, group_ids, REQUEST=REQUEST
         )
-        formsemestre_id = groups_infos.formsemestre_id
-        sem = sco_formsemestre.do_formsemestre_list(
-            self, {"formsemestre_id": formsemestre_id}
-        )[0]
         H = [self.sco_header(page_title="Etat des absences", REQUEST=REQUEST)]
         if date:
-            dateiso = DateDMYtoISO(date)
+            dateiso = notesdb.DateDMYtoISO(date)
             nbetud = 0
             t_nbabsjustam = 0
             t_nbabsam = 0
             t_nbabsjustpm = 0
             t_nbabspm = 0
-            etuds = self.getEtudInfoGroupes(groups_infos.group_ids)
-            H.append("<h2>Etat des absences le %s</h2>" % date)
+            H.append("<h2>État des absences le %s</h2>" % date)
             H.append(
                 """<table border="0" cellspacing="4" cellpadding="0">
              <tr><th>&nbsp;</th>
@@ -1738,7 +1728,7 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
             etudid=etudid, code_nip=code_nip, REQUEST=REQUEST, filled=True
         )
         if not etuds:
-            return log_unknown_etud(self, REQUEST=REQUEST)
+            return scu.log_unknown_etud(self, REQUEST=REQUEST)
         etud = etuds[0]
         # check dates
         begin_date = ParseDateTimeUTC(begin)  # may raises ValueError
@@ -1763,7 +1753,7 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
         if xml_reply:
             # Renvoie le nouveau billet en XML
             if REQUEST:
-                REQUEST.RESPONSE.setHeader("content-type", XML_MIMETYPE)
+                REQUEST.RESPONSE.setHeader("content-type", scu.XML_MIMETYPE)
 
             billets = billet_absence_list(cnx, {"billet_id": billet_id})
             tab = self._tableBillets(billets, etud=etud)
@@ -1884,11 +1874,10 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
     security.declareProtected(ScoView, "listeBilletsEtud")
 
     def listeBilletsEtud(self, etudid=False, REQUEST=None, format="html"):
-        """Liste billets pour un etudiant
-        """
+        """Liste billets pour un etudiant"""
         etuds = self.getEtudInfo(etudid=etudid, filled=1, REQUEST=REQUEST)
         if not etuds:
-            return log_unknown_etud(self, format=format, REQUEST=REQUEST)
+            return scu.log_unknown_etud(self, format=format, REQUEST=REQUEST)
 
         etud = etuds[0]
         cnx = self.GetDBConnexion()
@@ -1899,8 +1888,7 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
     security.declareProtected(ScoView, "XMLgetBilletsEtud")
 
     def XMLgetBilletsEtud(self, etudid=False, REQUEST=None):
-        """Liste billets pour un etudiant
-        """
+        """Liste billets pour un etudiant"""
         if not self.get_preference("handle_billets_abs"):
             return ""
         t0 = time.time()
@@ -1937,8 +1925,7 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
     security.declareProtected(ScoAbsChange, "deleteBilletAbsence")
 
     def deleteBilletAbsence(self, billet_id, REQUEST=None, dialog_confirmed=False):
-        """Supprime un billet.
-        """
+        """Supprime un billet."""
         cnx = self.GetDBConnexion()
         billets = billet_absence_list(cnx, {"billet_id": billet_id})
         if not billets:
@@ -2107,8 +2094,8 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
 
         Abs = self._ListeAbsDate(etud["etudid"], beg_date, end_date)
 
-        REQUEST.RESPONSE.setHeader("content-type", XML_MIMETYPE)
-        doc = jaxml.XML_document(encoding=SCO_ENCODING)
+        REQUEST.RESPONSE.setHeader("content-type", scu.XML_MIMETYPE)
+        doc = jaxml.XML_document(encoding=scu.SCO_ENCODING)
         doc.absences(etudid=etud["etudid"], beg_date=beg_date, end_date=end_date)
         doc._push()
         for a in Abs:
@@ -2126,7 +2113,7 @@ ou entrez une date pour visualiser les absents un jour donné&nbsp;:
         return repr(doc)
 
 
-_billet_absenceEditor = EditableTable(
+_billet_absenceEditor = notesdb.EditableTable(
     "billet_absence",
     "billet_id",
     (
@@ -2210,7 +2197,6 @@ def MonthTableTail():
 def MonthTableBody(
     month, year, events=[], halfday=0, trattributes="", work_saturday=False, pad_width=8
 ):
-    # log('XXX events=%s' % events)
     firstday, nbdays = calendar.monthrange(year, month)
     localtime = time.localtime()
     current_weeknum = time.strftime("%U", localtime)
@@ -2443,8 +2429,8 @@ class CAbsSemEtud:
         self.sem = sco_formsemestre.get_formsemestre(
             self.context, self.sem["formsemestre_id"]
         )
-        debut_sem = DateDMYtoISO(self.sem["date_debut"])
-        fin_sem = DateDMYtoISO(self.sem["date_fin"])
+        debut_sem = notesdb.DateDMYtoISO(self.sem["date_debut"])
+        fin_sem = notesdb.DateDMYtoISO(self.sem["date_fin"])
 
         self._CountAbs = self.context.Absences.CountAbs(
             etudid=self.etudid, debut=debut_sem, fin=fin_sem