Make parsing more robust (close #428, close #429)

Author: nils-herrmann

pybliometrics/scopus/abstract_retrieval.py

@@ -450,7 +450,7 @@ def isbn(self) -> tuple[str, ...] | None:
         if len(isbns) == 0:
             return None
         else:
-            return tuple((i['$'] for i in isbns))
+            return tuple(i['$'] if isinstance(i, dict) else str(i) for i in isbns)
 
     @property
     def issn(self) -> ISSN | None:
@@ -839,7 +839,7 @@ def __init__(self,
             self._json = self._json['abstracts-retrieval-response']
         self._head = chained_get(self._json, ["item", "bibrecord", "head"], {})
         conf_path = ['source', 'additional-srcinfo', 'conferenceinfo', 'confevent']
-        self._confevent = chained_get(self._head, conf_path, {})
+        self._confevent = chained_get(self._head, conf_path, {}) or {}
         if self._view == "REF":
             ref_path = ["references"]
         else:

pybliometrics/scopus/tests/test_AbstractRetrieval.py

@@ -34,6 +34,10 @@
 ab12 = AbstractRetrieval('2-s2.0-85044008512', view='FULL', refresh=30)
 # List of contributors in contributor group
 ab13 = AbstractRetrieval("2-s2.0-85038825012", view="FULL", refresh=30)
+# None in confcode
+ab14 = AbstractRetrieval("2-s2.0-79960092540", view="FULL", refresh=30)
+# Single isbn
+ab15 = AbstractRetrieval("2-s2.0-14544289566", view="FULL", refresh=30)
 
 
 def test_abstract():
@@ -129,6 +133,7 @@ def test_chemials():
 def test_confcode():
     assert ab2.confcode == 44367
     assert ab8.confcode is None
+    assert ab14.confcode is None
 
 
 def test_confdate():
@@ -320,6 +325,7 @@ def test_isbn():
     assert ab3.isbn is None
     assert ab5.isbn == ('0203881486', '9780203881484')
     assert ab8.isbn is None
+    assert ab15.isbn == ('0780385969',)
 
 
 def test_issn():