environment/lib/python2.7/site-packages/IPython/utils/jsonutil.py
def date_default(obj):
    """default function for packing datetime objects in JSON."""
    if isinstance(obj, datetime):
        return obj.strftime(ISO8601)
    else:
        raise TypeError("%r is not JSON serializable"%obj)
def date_default(obj):
    """default function for packing datetime objects in JSON."""
    if isinstance(obj, datetime):
        return obj.strftime(ISO8601)
    else:
        raise TypeError("%r is not JSON serializable"%obj)
default function for packing datetime objects in JSON.