new_contents: def integratePlanarOrbit_leapfrog(pot,yo,t,rtol=None,atol=None):
      """
      NAME:
         integratePlanarOrbit_leapfrog
      PURPOSE:
         leapfrog integrate an ode for a planarOrbit
      INPUT:
         pot - Potential or list of such instances
         yo - initial condition [q,p]
         t - set of times at which one wants the result
         rtol, atol
      OUTPUT:
         y : array, shape (len(y0), len(t))
         Array containing the value of y for each desired time in t, \
         with the initial value y0 in the first row.
      HISTORY:
         2011-10-03 - Written - Bovy (NYU)
      """
      
  
subject: add python C wrapper; mostly empty for now