code: def _check_voSet(orb,kwargs,funcName):
      
      if not orb._voSet and kwargs.get('vo',None) is None:
          warnings.warn("Method %s(.) requires vo to be given at Orbit initialization or at method evaluation; using default vo which is %f km/s" % (funcName,orb._vo),
                        galpyWarning)
docs: Function to check whether vo is set, because it's required for funcName