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

       evaluateplanarphiforces

    PURPOSE:

       evaluate the phiforce 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_phi(R(,phi,t))

    HISTORY:

       2010-07-13 - Written - Bovy (NYU)

    """
    return _evaluateplanarphiforces(Pot,R,phi=phi,t=t)
NAME:

       evaluateplanarphiforces

    PURPOSE:

       evaluate the phiforce 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_phi(R(,phi,t))

    HISTORY:

       2010-07-13 - Written - Bovy (NYU)