How to resolve this?

File "convert-script.py", line 1, in
import coremltools
File "/Users/anujgoyal/Environments/python27/lib/python2.7/site-packages/coremltools/init.py", line 28, in
_root_logger_handlers_backup = _root_logger.handlers.copy()
AttributeError: ‘list’ object has no attribute ‘copy’