On rend plus robuste l'import (dans le cas où il manque des informations)

src/agenda_culturel/extractors.py

@@ -144,10 +144,15 @@ class ExtractorFacebook(Extractor):
                         self.get_neighbor_events(event[k])
                     elif k in ExtractorFacebook.FacebookEvent.rules:
                         for nk, rule in ExtractorFacebook.FacebookEvent.rules[k].items():
+                            error = False
                             c = event[k]
                             for ki in rule:
-                                c = c[ki]
-                            self.elements[nk] = c
+                                if c is not None:
+                                    c = c[ki]
+                                else:
+                                    error = True
+                            if not error:
+                                self.elements[nk] = c
                     else:
                         self.elements[k] = event[k]