Traceback (most recent call last):

 "gyb.py", line 1503, in <module>
main(sys.argv[1:])

 "gyb.py", line 925, in main
detect_types=sqlite3.PARSE_DECLTYPES)sqlite3.OperationalError: unable to open database file
Traceback (most recent call last):

 "tests/dg.py", line 3, in <module>
cores=nx.find_cores(G)

 "/home/aric/Software/networkx-trunk/networkx/algorithms/core.py", line 87, in core_number
nbrs[u].remove(v)KeyError: 3