def evaluateplanarR2derivs(Pot,R,phi=None,t=0.):
    """
    NAME:

       evaluateplanarR2derivs

    PURPOSE:

       evaluate the second radial derivative of a (list of) planarPotential instance(s)

    INPUT:

       Pot - (list of) planarPotential instance(s)

       R - Cylindrical radius (can be Quantity)

       phi= azimuth (optional; can be Quantity)

       t= time (optional; can be Quantity)

    OUTPUT:

       F_R(R(,phi,t))

    HISTORY:

       2010-10-09 - Written - Bovy (IAS)

    """
    from .Potential import _isNonAxi
    isList= isinstance(Pot,list)
    nonAxi= _isNonAxi(Pot)
    if nonAxi and phi is None:
        raise PotentialError("The (list of) planarPotential instances is non-axisymmetric, but you did not provide phi")
    if isinstance(Pot,list) \
            and nu.all([isinstance(p,planarPotential) for p in Pot]):
        sum= 0.
        for pot in Pot:
            if nonAxi:
                sum+= pot.R2deriv(R,phi=phi,t=t,use_physical=False)
            else:
                sum+= pot.R2deriv(R,t=t,use_physical=False)
        return sum
    elif isinstance(Pot,planarPotential):
        if nonAxi:
            return Pot.R2deriv(R,phi=phi,t=t,use_physical=False)
        else:
            return Pot.R2deriv(R,t=t,use_physical=False)
    else: #pragma: no cover 
        raise PotentialError("Input to 'evaluatePotentials' is neither a Potential-instance or a list of such instances")
NAME:

       evaluateplanarR2derivs

    PURPOSE:

       evaluate the second radial derivative of a (list of) planarPotential instance(s)

    INPUT:

       Pot - (list of) planarPotential instance(s)

       R - Cylindrical radius (can be Quantity)

       phi= azimuth (optional; can be Quantity)

       t= time (optional; can be Quantity)

    OUTPUT:

       F_R(R(,phi,t))

    HISTORY:

       2010-10-09 - Written - Bovy (IAS)