some attributes don't work

oml/media/pdf.py

@@ -149,7 +149,10 @@ def info(pdf):
             if xmp:
                 for key in dir(xmp):
                     if key.startswith('dc_'):
-                        value = getattr(xmp, key)
+                        try:
+                            value = getattr(xmp, key)
+                        except:
+                            continue
                         if isinstance(value, dict) and 'x-default' in value:
                             value = value['x-default']
                         elif isinstance(value, list):