Update RecordThesis to work with attirbute df_authors

modules/store_tools/recordthesis.py

@@ -35,7 +35,7 @@ class RecordThesis(RecordPubli):
         """
         # for a thesis, the authors field contains names of author
         # as well as those of directors. The latter have to be removed.
-        df = self[u"authors"]
+        df = self.df_authors
 
         if "relator_name" in df:
             df = df[df.relator_name != THESIS_DIR]
@@ -60,46 +60,46 @@ class RecordThesis(RecordPubli):
         """The defence date for a master/phd thesis.
 
         Returns:
-            unicode:
+            str:
                 * The pattern is not standardise
                   and can varies between records and between stores.
                 * The filter CLEAN_THESIS_DEFENSE is applied.
 
         """
-        val = self._get(u"dissertation_note", u"defense_date")
+        val = self._get("dissertation_note", "defense_date")
         return CLEAN_THESIS_DEFENSE(val)
 
     def these_level(self):
         """The level of the thesis.
 
         Returns:
-            unicode:
+            str:
                 * The value is ``master`` or ``PhD``.
                 * The value is not standardise and can varies
                   between records and between stores.
                 * Empty string when not defined
 
         """
-        return self._get(u"dissertation_note", u"diploma")
+        return self._get("dissertation_note", "diploma")
 
-    def these_directors(self, sep=u", "):
+    def these_directors(self, sep=", "):
         """The list of director(s)
 
         Returns:
-            unicode:
+            str:
                 * Names are separated by the ``sep`` argument.
                 * Empty string when it is not defined.
 
         """
         # for a thesis, the author field 700 field contains
         # names of the director as well as the name of authors
-        df = self[u"authors"]
+        df = self.df_authors
 
         if "relator_name" in df:
             query = df.relator_name == THESIS_DIR
             df = df.loc[query]
 
-            return (sep.join(df.fmt_name) if len(df) > 0 else u"")
+            return (sep.join(df.fmt_name) if len(df) > 0 else "")
 
         else:
             return ""
@@ -108,9 +108,9 @@ class RecordThesis(RecordPubli):
         """The university(ies) delivering the thesis diploma.
 
         Returns:
-            unicode:
+            str:
                 - empty when university(ies) is not defined
                 - several university are separated by ``&`` character.
 
         """
-        return self._get(u"dissertation_note", u"university")
+        return self._get("dissertation_note", "university")