def FZStaeckel(u,v,pot,delta): #pragma: no cover because unused
    """
    NAME:
       FZStaeckel
    PURPOSE:
       return the vertical force
    INPUT:
       u - confocal u
       v - confocal v
       pot - potential
       delta - focus
    OUTPUT:
       FZ(u,v)
    HISTORY:
       2012-11-30 - Written - Bovy (IAS)
    """
    R,z= bovy_coords.uv_to_Rz(u,v,delta=delta)
    return _evaluatezforces(pot,R,z)
def FZStaeckel ( u , v , pot , delta ) : R , z = bovy_coords . uv_to_Rz ( u , v , delta = delta ) return _evaluatezforces ( pot , R , z )
NAME:
       FZStaeckel
    PURPOSE:
       return the vertical force
    INPUT:
       u - confocal u
       v - confocal v
       pot - potential
       delta - focus
    OUTPUT:
       FZ(u,v)
    HISTORY:
       2012-11-30 - Written - Bovy (IAS)