>>> import krpc
>>> conn = krpc.connect("blah")
>>> sc = conn.space_center
>>> vessel = sc.launchable_vessels("vab")[0]
>>> sc.launch_vessel_from_vab(vessel)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <lambda>
  File "/Users/jimbo/.virtualenvs/kerbal/lib/python3.6/site-packages/krpc/client.py", line 140, in _invoke
    raise self._build_error(response.results[0].error)
krpc.error.RPCError: Method not found: 'KerbalRoster.DefaultCrewForVessel'.
Server stack trace:
  at KRPC.SpaceCenter.Services.SpaceCenter.LaunchVessel (System.String craftDirectory, System.String name, System.String launchSite, Boolean recover) [0x00000] in <filename unknown>:0 
  at KRPC.SpaceCenter.Services.SpaceCenter.LaunchVesselFromVAB (System.String name, Boolean recover) [0x00000] in <filename unknown>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0