for non-list potentials, use instance methods epifreq and verticalfreq for general functions (helps with interpRZPotential which doesn't implement the second derivatives but does implement the epifreq and verticalfreq (#201)
for non-list potentials, use instance methods epifreq and verticalfreq for general functions (helps with interpRZPotential which doesn't implement the second derivatives but does implement the epifreq and verticalfreq (#201)

jobovy/galpy,followthesheep/galpy,followthesheep/galpy,followthesheep/galpy,jobovy/galpy,jobovy/galpy,followthesheep/galpy,jobovy/galpy