'The acceleration Vector of this Point in a ReferenceFrame.
Parameters
frame : ReferenceFrame
The frame in which the returned acceleration vector will be defined in
Examples
>>> from sympy.physics.vector import Point, ReferenceFrame
>>> N = ReferenceFrame(\'N\')
>>> p1 = Point(\'p1\')
>>> p1.set_acc(N, 10 * N.x)
>>> p1.acc(N)
10*N.x'

def acc(self, frame):

    _check_frame(frame)
    if (not (frame in self._acc_dict)):
        if (self._vel_dict[frame] != 0):
            return self._vel_dict[frame].dt(frame)
        else:
            return Vector(0)
    return self._acc_dict[frame]
