correct typo in adjlist.py: check_multiplicity
correct typo in adjlist.py: check_multiplicity

if multiplicity is even, then we have a problem.

comocheng/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,enochd/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,nickvandewiele/RMG-Py,enochd/RMG-Py,chatelak/RMG-Py,comocheng/RMG-Py