deposits: fix swisscovery import

* Fixes error on 502 fields on leader function.
* Fixes extract date on 100 or 700 field.
* Closes rero#674.

Co-Authored-by: Bertrand Zuchuat <bertrand.zuchuat@rero.ch>
Co-Authored-by: Peter Weber <peter.weber@rero.ch>

sonar/modules/documents/dojson/sru/model.py

@@ -404,7 +404,11 @@ def marc21_to_contribution_from_100_700(self, key, value):
     data = {'agent': {'type': type, 'preferred_name': name}, 'role': [role]}
 
     if is_100_or_700 and value.get('d'):
-        date_of_birth, date_of_death = overdo.extract_date(value['d'][:9])
+        date_of_birth = date_of_death = None
+        try:
+            date_of_birth, date_of_death = overdo.extract_date(value['d'][:9])
+        except Exception:
+            pass
 
         if date_of_birth:
             data['agent']['date_of_birth'] = date_of_birth
@@ -539,8 +543,8 @@ def marc21_to_document_type_from_leader(self, key, value):
         if leader_07 == 's':
             return 'coar:c_2659'
 
-        field_502 = overdo.blob_record.get('502__')
-        if field_502:
+        fields_502 = overdo.blob_record.get('502__')
+        for field_502 in fields_502:
             # Bachelor thesis
             if 'bachelor' in field_502.get(
                     'a', '') or 'bachelor' in field_502.get('b', ''):