indexing error for things

during things indexing:

A major error prevented the ingestion of LINCS data:
Traceback (most recent call last):
  File "/apps/corpora/plugins/lincs/tasks.py", line 95, in index_LINCS
    ingest(sparql_endpoint, corpus, job, sparql_user, sparql_pw, limit)
  File "/apps/corpora/plugins/lincs/tasks.py", line 463, in ingest
    thing.decades = list(set([x - (x%10) for x in thing.years]))
  File "/apps/corpora/plugins/lincs/tasks.py", line 463, in 
    thing.decades = list(set([x - (x%10) for x in thing.years]))
TypeError: unsupported operand type(s) for %: 'datetime.datetime' and 'int'